dissenting:
The majority reverses the summary judgment order and remands to the trial court the issue of whether Jack Taylor, the applicant in the 1960 Torrens action, exercised *1230reasonable diligence to identify parties who should have been named personally and should have received direct notice of the suit through personal service. I disagree. The notice required by statute, found by the federal district court to have been “met and fulfilled,” and affirmed by the Tenth Circuit, satisfied the requirements of due process. I believe that the plaintiffs are barred by res judicata from relitigating the issues of the 1960 case. In my opinion, reopening the question of rights in property determined over thirty years ago is counter to the public policy of this state because it creates uncertainty in the conclusiveness of quiet title decisions and fails to keep title secure and marketable. For these reasons, I dissent.
I.
I agree with the trial court and the court of appeals that the plaintiffs are barred by res judicata from bringing this suit. Res judicata bars relitigation of a prior action when the two suits share the same subject matter, the same cause of action, and the same parties.1 Newby v. Bock, 120 Colo. 454, 210 P.2d 985 (1949). Because the plaintiffs and their predecessors in interest received adequate notice of the 1960 action, they were parties to it. Their due process rights were not violated and they are now barred by res judicata from relitigating the same issues that were decided in that case over thirty years ago.
The Torrens Act specifically provides for notice to known and unknown potential claimants. Section 38-36-121, 16A C.R.S. (1982), requires that known, resident defendants be personally served with a summons, but that non-resident defendants and “all such unknown persons or parties” be served only by publication. Under the Act, all potential claimants, known and unknown, are made parties to the action. § 38-36-126, 16A C.R.S. (1982).
In the 1960 action, Taylor complied with all of the notice requirements of the Torrens Act. As the majority notes on page 1214 of its opinion, Taylor’s application listed 316 individuals as potential defendants, even though only forty-seven of those names appeared in the abstract of title. The remaining names on the list were those landowners in the county who might claim usufructuary rights to the pasture and timber. Attorneys for potential claimants added an additional 142 names to the list.
In accordance with the Torrens Act, the federal district court appointed a title examiner, who submitted a report to the court. According to his report, the examiner studied the abstract of title and personally investigated the occupancy of the Mountain Tract. He also made inquiry with the county treasurer, the county assessor, and other persons familiar with the land to identify potential defendants to the action. His report indicated that “various persons claim rights to take pasture and wood from The Mountain Tract and an unincorporated organization called the ‘Association of Civic Rights!,]’ whose members are named in the petition, assert such rights on behalf of themselves and other persons.” The report stated that these rights were claimed under a grant made by Carlos Beaubien on May 11, 1863 (the Beau-bien grant), which was located in the county land records.2 The title examiner sought to learn the identities of these “other persons.” He contacted the attorney for several defendants in a similar, but unrelated, lawsuit.' The attorney tried to obtain the names but was unsuccessful. He also talked with a representative of the Association of Civic Rights, who also could not provide any specific names.
In addition to the parties identified in the petition and by the title examiner, other possible claimants were designated as “persons or parties unknown.” These “unknown” defendants were served by publication of the summons for six weeks in a newspaper of general circulation in Costilla County.
*1231The named defendants were represented by several attorneys. The court also appointed a guardian ad litem “to represent minors and other persons under disability and all other persons who may have an interest in this proceeding.” On July 31, 1962, the federal district court entered default against 369 defendants for failure to answer interrogatories. The case proceeded against the 112 remaining defendants.
The defendants asserted communal rights to use the Mountain Tract for pasture land and to take wood. They based their claims on Spanish or Mexican law; as beneficiaries under the Sangre de Cristo grant, in which the government of Mexico granted land to Narcisco Beaubien; the Treaty of Guadalupe Hidalgo; and on the 1863 document signed by Carlos Beaubien specifically granting usu-fructuary rights. The federal district court concluded that, as a matter of federal law, the communal rights under the Sangre de Cristo grant and the Treaty of Guadalupe Hidalgo were extinguished when title to the land was confirmed in Beaubien by an act of Congress in 1860. The district court also found that the communal rights established under the Beaubien document applied to the “lands of the Rito Seco,” which were not part of the Mountain Tract. Even if the grant of usufructuary rights under the Beaubien document remained valid, therefore, it did not apply to the Mountain Tract. A final decree was entered on October 8, 1965. The decree vested fee simple title to the Mountain Tract in Jack Taylor, free of any claims of all persons, known and unknown. The defendants then appealed the decision to the Tenth Circuit, which affirmed the district court on all issues.
I believe that the plaintiffs in the current action, or their predecessors in interest, received proper notice of the Torrens action and that their due process rights were not violated. They had not recorded any interest in the land and did not occupy it.3 They were thus included among the group of “unknown” potential claimants and were properly served by publication according to section 38-36-121.
The federal district court, in its “Final Decree of Confirmation of Title and Registration” of 1965, also concluded that notice was properly given to the defendants in the earlier case. The court noted that it had jurisdiction of the parties and the subject matter, and that “the statutory requirements of service, publication and notice have been met and fulfilled.” As against a collateral attack on a prior court’s jurisdiction, “the judgment of a court of record is supported by the conclusive presumption that jurisdiction was obtained of the party against whom it was pronounced, unless the contrary affirmatively appears from the record.” Hughes v. Webster, 52 Colo. 475, 122 P. 789 (1912). There is no indication in the record of the 1960 case, insofar as it is before this court, that proper notice of the suit was at issue, nor that notice by publication was not sufficient. The plaintiffs may not relitigate the issue of whether notice was adequate.
II.
The majority holding requires a Torrens Act plaintiff to exercise “reasonable diligence” to ascertain the identities of otherwise “unknown” claimants, that is, claimants whose names or interests do not appeal’ in the record chain of title and who are not in possession of the land. I do not believe that there is such a duty, nor that the jurisprudence of other states supports one.
The majority cites nine cases from other jurisdictions for the proposition that a Torrens plaintiff, such as Taylor in this case, must exercise reasonable diligence in locating “unknown” potential claimants in order to effect personal service. I disagree with the majority’s interpretation of these cases. The cases cited in the majority opinion all involve potential claimants who were not notified, but who were known or should have been known to the plaintiff through the chain of title, through public records, or because they *1232were in possession of the land. Those courts found that the plaintiff should have exercised diligence to find and notify those known potential claimants by searching the public records in which they were identified.
In the first case cited by the majority, Follette v. Pacific Light & Power Corp., 189 Cal. 193, 208 P. 295 (1927), the Torrens Act plaintiff granted a right-of-way easement to Pacific Light & Power Corporation. The easement was recorded and the grantee took possession of that portion of the land. The grantor then filed a Torrens action, but did not notify the utility company other than by publication. Subsequent owners of the property relied on the certificate of title issued in the Torrens action. When Follette, a subsequent owner of the property, learned of the easement and sought to eject the utility company, the court ruled that the certificate of title issued to the original grantor was void as against the utility company, because, as an occupant of the land in question, the utility company should have received personal service. The court contrasted the utility company with those who needed only to receive notice by publication: “The provisions of the act as to publication of notice can have application only to those who were not in the possession or occupancy of the premises.” Id. 208 P. at 299.
The next case relied on by the majority, Robinson v. Kerrigan, 151 Cal. 40, 90 P. 129 (1907), involved a general constitutional challenge to California’s Torrens Act. The court found constitutional the provisions of the act for personal notice to all the parties shown by the application or' by the abstract of title to have an interest in the property, to the spouse of the petitioner, and to the owners of the adjoining land. The court also found that service on all other persons could be by publication. Contrary to the majority’s assertion, there is no discussion of personal notice to “reasonably ascertainable” claimants, nor of any duty placed on the plaintiff to directly notify anyone but the specific parties noted above.
The majority next cites State v. Guilbert, 56 Ohio St. 575, 47 N.E. 551 (1897), which it claims held that a Torrens statute that did not require an applicant to personally serve all reasonably ascertainable claimants was unconstitutional for lack of due process. Guilbert is inapposite because it construed a version of the Torrens Act very different from the one in place in Colorado. Neither does the case impose a duty on the plaintiff to seek out “reasonably ascertainable” claimants. The Ohio statute at issue in that case provided for personal service only upon owners of adjacent land, upon the occupant of the land, and upon holders of easements and inferior estates in the land. All others could be served by publication. The court held the statute unconstitutional because the plaintiff was not required to give personal notice to those whom he knew had adverse claims against the property, including one who held the title in fee simple absolute.4 That court further buttressed its reasoning by declaring that Torrens actions were actually in person-am actions, not in rem actions, and thus would require personal notice.5
The majority cites an additional six cases for the proposition that “[ojther courts have recognized a requirement of diligent inquiry into the identity of all reasonably ascertainable claimants under their states’ Torrens statutes.” Maj. op. at 1227 n. 25. Each one *1233of these cases, however, involved claimants whose interests appeared in county land records, were named in the examiner’s abstract, were in possession, or of whose interests the applicant had actual knowledge. They do not support the majority’s contention that a Torrens applicant has a duty to search for potential claimants beyond those who have a record interest in the property or those whose interests are known or should be known because of their possession of the land.
In Moakley v. Los Angeles Pacific Railway Co., 99 Cal.App. 74, 277 P. 883 (1929), the Torrens plaintiff did not name or notify a claimant whose easement was recorded and appeared in the abstract of title. The claimant in Coney v. Talalah Estates Corp., 183 Ga. 442, 188 S.E. 822 (1936), was known to the Torrens plaintiff to have an interest in the property, was in possession of the land, and was also an adjoining landowner. The statute required notice based on any of these conditions, but none was given. In Chicago Title & Trust Co. v. Darley, 363 Ill. 197, 1 N.E.2d 846 (1936), the claimant was in possession of the land at the time the Torrens action was filed, used the land for farming, and maintained fences on the property, but still received no notice. In Sheaff v. Swindler, 339 Ill. 540, 171 N.E. 632 (1930), the Torrens applicant failed to name the fee simple owner of record and the tenant in possession of the property. He admitted that he knew of the ownership and possession when he filed the Torrens action. In contrast to the other cases cited by the majority, this one does mention the necessity of “diligent inquiry.” By this phrase, however, the court imposed a duty of diligent inquiry to search the public records for recorded interests in the land. The Torrens plaintiff in Deivey v. Kimball, 89 Minn. 454, 95 N.W. 317 (1903), failed to name in her application the owner of the land who was listed in the records of the county auditor and that party’s successor in interest, despite the recommendation of the examiner that these parties be named and notified. Although the name of the successor was not in the public records, the court held that the plaintiff would have learned it if she' had notified the record owner. Finally, as the majority notes, Baart v. Martin, 99 Minn. 197, 108 N.W. 945 (1906), involved intentional fraud when the Torrens plaintiff failed to name and notify the record holder of a mortgage, of whom he was aware.
None of these nine cases imposed a duty on the Torrens applicant to search for a potential claimant beyond public records or beyond inspecting the land to ascertain who was in possession. In all of the cases, the Torrens certificate was later held to be invalid because the. plaintiff failed to name and notify a claimant who was listed in public records or was in possession. The majority asserts that courts in other states have imposed a heightened duty of “diligent inquiry into the identity of all reasonably ascertainable claimants.” They have not. I do not believe these cases support this claim.
III.
The correct standard to determine whether notice provided satisfies due process is articulated in Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 70 S.Ct. 652, 94 L.Ed. 865 (1950), and its progeny. “The means employed [to provide notice] must be such as one desirous of actually informing the absentee might reasonably adopt to accomplish it. The reasonableness and hence the constitutional validity of any chosen method may be defended on the ground that it is in itself reasonably certain to inform those affected.” Id. at 315, 70 S.Ct. at 657-58. Mullane does not require that the best means of giving notice be employed, only the most reasonable. Id. at 317, 70 S.Ct. at 658-59. Under Mullane, personal service is not an indispensable element of the right to due process.6
*1234Mullane involved the question of whether beneficiaries of a trust received adequate notice of the disposition of trust accounts. The state statute only required notice by publication. The Mullane court held that publication notice was adequate only for those beneficiaries “whose interests or whereabouts could not with due diligence be ascertained.” Id. In that ease, the trustee was required to provide actual notice to the beneficiaries whose names and addresses were in his records. However, the court also held that publication notice was adequate for “those beneficiaries whose interests ... could be discovered upon investigation, [but] do not in due course of business come to knowledge of the common trustee.” Id. The court further stated that there was no requirement of “impracticable and extended searches” to locate those beneficiaries whose interests were remote. Id. One is not required to undertake “extraordinary efforts to discover the identity and whereabouts of a [claimant] whose identity is not in the public record.” Mennonite Bd. of Missions v. Adams, 462 U.S. 791, 799 n. 4, 103 S.Ct. 2706, 2711 n. 4.
Based on Mullane and its progeny, I find that Jack Taylor provided adequate notice to potential claimants. He not only complied with the notice requirements of the Torrens statute, but also named and notified 316 parties whose names and interests were not found in the public records. By order of the court, he also named and notified 142 additional potential claimants. The record also indicates that the title examiner actively sought to identify other potential claimants.
I conclude that Taylor’s 1960 action not only satisfied due process standards, but went significantly beyond what due process required. Even if we were to read the statute to impose a requirement of reasonable diligence, I believe that reasonable diligence was exercised.
IV.
Because the interests of the “unknown” claimants were represented in the 1960 action, their due process rights were not infringed. The record indicates that the court appointed a guardian ad litem to represent the interests of the “unknown” claimants.
Moreover, because the usufructuary rights in question were the same rights shared by all of the potential claimants, the fact that most of the claimants received notice and had an opportunity to participate in the suit was sufficient to protect the interests of those who did not. “[N]otiee reasonably certain to reach most of those interested in objecting is likely to safeguard the interests of all, since any objection sustained would inure to the benefit of all. We think that under such circumstances reasonable risks that notice might not actually reach every [claimant] are justifiable.” Mullane, 339 U.S. at 319, 70 S.Ct. at 659-60.
*1235The interests of the “unknown” claimants were represented in the 1960 action. As successors in interest to those “unknown” claimants, the current plaintiffs are bound by the results of that earlier decision.
V.
The plaintiffs’ attempt to void the 1960 Torrens action and the majority’s acquiescence in their collateral attack results in the application of an incorrect remedy. According to section 38-36-131(1), 16A C.R.S. (1982), parties in the position of the plaintiffs, who claim they should have received actual notice of the Torrens action but did not, may reopen the decree only within ninety days after entry of the decree, and not afterwards. In this case, the final decree was not entered until October 5,1965. The plaintiffs, or their predecessors in interest, had five years from the original filing to become aware of the Torrens action. Because they did not attack the decree within the statutory ninety days, they are now prohibited from doing so.
Section 38-36-131(2), 16A C.R.S. (1982), provides the appropriate remedy. If, as the plaintiffs claim, Taylor’s application in the Torrens action was made with fraudulent intent, their correct remedy is a suit for damages. “Any person aggrieved by such decree in any case may pursue his remedy by suit in the nature of an action of tort against the applicant or any other person for fraud in procuring the decree.... ” § 38-36-131(2). Reopening the thirty-year-old decree is not the proper remedy. See White v. Ainsworth, 62 Colo. 513, 163 P. 959 (1917).
VI.
The effect of the majority opinion is to reopen a thirty-year-old decision and put into question the ownership of a considerable portion of the land in Costilla County. The plaintiffs’ second amended complaint names as defendants not only the estate and heirs of Jack Taylor, but an additional 218 parties and “all unknown persons” who now may have ownership or other interests in the land.
It is the public policy of this state to make title to property more secure and marketable, not less. See § 38-34-101, 16A C.R.S. (1993 Supp.).
[A]U ... laws concerning or affecting title to real property and every interest therein and all recorded instruments, decrees, and orders of courts of record ... shall be liberally construed with the end in view of rendering such titles absolute and free from technical defects so that subsequent purchasers ... may rely on the record title and so that the record title of the party in possession is sustained and not defeated by technical or strict constructions.
Id. The majority opinion directly contradicts this legislative prescription by allowing a party, after any period of time, to reopen dispositions of land title. The majority does violence to this state’s system of securing title and irreparably harms the marketability of land in this state. The majority opinion reaches not only titles obtained through Torrens actions, but also, by implication, all land ownership determinations made in quiet title actions. The provisions for naming defendants in quiet title actions and providing them notice differ little from similar provisions in the Torrens Act.7
The effect of the majority’s decision is to create uncertainty in the conclusiveness of land title in this state.
VII.
The majority holds that summary judgment was inappropriate in this case because a question of fact remained as to whether Taylor exercised reasonable diligence in identifying potential claimants who should have been named parties and should have received notice of the action through service of process. The crux of the issue, as posed by the majority, is whether Taylor’s efforts and the notice that he provided was adequate to reach the predecessors in interest of the current plaintiffs. The majority remands this issue to the trial court for a factual determination. This remand is an incorrect disposition of the case. The question of the sufficiency of notice is one of law, not of fact. Closed Basin Landowners Ass’n v. Rio *1236Grande Water Conservation Dist., 734 P.2d 627 (Colo.1987); Kavanagh v. Hamilton, 53 Colo. 157, 125 P. 512 (1912) (holding that on collateral attack the jurisdiction of a court of record must be determined by its own record). As such, even if we choose to graft the requirement of applying reasonable diligence in locating unknown claimants onto the Torrens Act, the decision on whether Taylor exercised that reasonable diligence is a question of law for this court, not a question of fact for the trial court.
VIII.
Because I believe that the plaintiffs are prohibited by res judicata from relitigating the 1960 action, and because notice in that suit was adequate to satisfy due process, I dissent. I also cannot agree that the plaintiffs should be allowed to reopen a thirty-year-old determination of land title. Such a result would introduce chaos and uncertainty in the marketability of land in this state.
I am authorized to say that Chief Justice ROVIRA and Justice ERICKSON join in this dissent.
. The “same parties” requirement is satisfied if the parties of the second suit are in privity with those of the first. Many of the plaintiffs in the current suit are heirs of the defendants from the 1960 suit. As successors in interest, they are in privity with the earlier parties. Green v. Chaffee Ditch Co., 150 Colo. 91, 371 P.2d 775 (1962).
. The Beaubien grant is set out in the majority opinion at page 1213.
. It may be argued that the Beaubien grant provides record notice of the plaintiffs' claim of usufructuary rights. However, as the federal district court and the Tenth Circuit found, the potential claimants could not rely on this grant because the rights under it were extinguished by the 1860 act of Congress. Furthermore, those courts also found that the rights given under the Beaubien grant pertained to another land parcel, not the Mountain Tract.
. The Ohio legislature later passed a revised version of the Torrens Act. It requires notice to any "person [who] to the knowledge or information of the applicant, or as shown by the records, has or claims any interest in the lands, buildings, or improvements.” Ohio Rev.Code Ann. §§ 5309.-09, 5309.12 (Anderson 1989). Unlike Colorado’s statute, the Ohio Torrens statute mentions the necessity of diligent inquiry to ascertain potential claimants: "When the names of any persons ... necessary or proper to be made parties defendant to an application, are unknown to the applicant after diligent inquiry and research," those parties are to be named in the petition as "unknown” and notified by publication. Ohio Rev. Code Ann. § 5309.12 (Anderson 1989). Unlike the Ohio legislature, however, the Colorado legislature chose not to include such language in its Torrens statute.
. It is, of course, of no import today whether the action is in personam or in rem, after Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 70 S.Ct. 652, 94 L.Ed. 865 (1950), Shaffer v. Heitner, 433 U.S. 186, 97 S.Ct. 2569, 53 L.Ed.2d 683 (1977), and Mennonite Board of Missions v. Adams, 462 U.S. 791, 103 S.Ct. 2706, 77 L.Ed.2d 180 (1983).
. The majority also relies on American Land Co. v. Zeiss, 219 U.S. 47, 31 S.Ct. 200, 55 L.Ed. 82 (1911), to support its contention that there is a duty to “make diligent inquiry to ascertain the names of all claimants.” That case did not involve the Torrens Act, but rather a similar California law passed a few months after the 1906 San Francisco earthquake and resultant fires that destroyed all public records of land ownership. As the majority correctly notes, the California Supreme Court interpreted the statute to require "diligent inquiry.” The actual holding of Zeiss, however, tends to refute the majority’s position rather than support it. Zeiss, the lessee *1234of the property in question, filed an action under the statute and alleged that he was the owner of the land and knew of no other person with a claim on it. However, he made no inquiry to ascertain whether any adverse claim existed. In compliance with the statute, notice was published in a local periodical. Zeiss received a certificate of title. The later suit was brought by the actual owners of the property in fee simple. The lower court dismissed their claim because Zeiss had obtained title through the earlier action. After reciting the language requiring "diligent inquiry,” the United States Supreme Court held the California statute to be constitutional, affirmed the lower court's dismissal, and denied the true owners their title to the property. The actual result of Zeiss was that a petitioner under the California statute could obtain title to property even though he made no inquiry beyond publication notice to ascertain whether there were claims against the property.
Mullane v. Central Hanover Bank & Trust Co., 339 U.S. 306, 70 S.Ct. 652, 94 L.Ed. 865 (1950), cited Zeiss, but differently than the majority suggests. Mullane quoted Zeiss for the proposition that notice should be practical and reasonable, but need not be given to every possible person who could conceivably have a claim:
But if with due regard for the practicalities and peculiarities of the case these conditions [i.e., interested parties are informed of the action and have an opportunity to present their objections] arc reasonably met, the constitutional requirements are satisfied. "The criterion is not the possibility of conceivable injury but the just and reasonable character of the requirements, having reference to the subject with which the statute deals.”
Mullane, 339 U.S. at 314-15, 70 S.Ct. at 657 (quoting Zeiss, 219 U.S. at 67, 31 S.Ct. at 207).
. See C.R.C.P. 105, 10(a), 9(a)(2), and 4.