delivered the opinion of the court.
*124The questions before us arise out of an action by plaintiff in error against defendant in error to recover upon a promissory note. The cause was tried to the court without a jury. Finding and judgment were for defendant.
In the plaintiff’s pleadings it is alleged that in 1910 plaintiff and one Orvey Williamson, on the solicitation of the defendant, bought sixty shares of stock in The Haigler Irrigation Company, which was at that time being promoted by the defendant, defendant agreeing that if they would purchase the same he would, at the expiration of three years, take up said stock and return to said purchasers the money paid therefor, with interest, should the investment prove unsatisfactory to them; that, relying wholly on defendant’s said promise, they purchased the said shares, and paid therefor to the defendant the- sum of $1200; that a certificate for said stock was issued to them, and that the defendant wrote upon the margin of the said certificate, before it was delivered, his personal guaranty, as above stated, and signed the same; that after the term of three years had elapsed, said parties elected to return the said stock and be paid the purchase price thereof, according to the agreement above set forth, and thereupon called upon defendant to pay said money to them; that he being unable to do so, they accepted his promissory note for said sum and interest, which was subsequently taken up by the note in suit, which was payable to plaintiff; that the said Retallic and the said Williamson were, at all times in the pleadings mentioned, joint owners of said stock and jointly interested in the said original note, and likewise so interested in the note sued upon; that said Retallic during his life time acted as agent and trustee of the said Williamson, in taking said promissory note, and the note in suit; that the executor of the said Retallic, who has been substituted as plaintiff herein is now acting in said capacity for the purpose of this suit with full knowledge, consent and approval of the said Williamson.
The amended answer admitted the execution of the note, *125and the giving of the guaranty, but alleged that the guaranty was made without consideration, and as the act of the company; that the plaintiff was not the owner of the note, and not the real party in interest; and that the note was without consideration.
On the trial said Williamson testified that in all of his dealings with the defendant he was acting for himself and the plaintiff; that the purchase of the stock was induced by an agreement of the defendant to repurchase it; that each paid one-half of said $1200; and that the stock certificate had been transferred to plaintiff, who held the same for himself and the witness.
Plaintiff then offered in evidence the following letter:
“Exhibit B.
December 8, 1910.
Mr. O. Williamson,
Barry, 111.
My Dear Orvey:
Herewith I enclose stock certificate No. 9 for sixty shares of stock as requested in your letter of the 6th.
I have also added my personal guarantee to the same as I said I would, leaving the matter optional with you. I will keep you posted from time to time as to the progress we are making.
With best regards, I remain
Yours very truly,
(Signed) William H. Dickson.”
Objection was made that the guaranty was not to the plaintiff; that the letter might be competent as against the defendant, if Williamson were suing, on a note involving it, but not in favor of the plaintiff in this action.
The objection was sustained, and the plaintiff then asked leave to join Williamson as joint plaintiff, which request was denied. The rejection of this letter, and the denying of the application to join Williamson as plaintiff, are assigned as error.
The plaintiff’s case, as pleaded, was that he and Wil*126liamson were joint owners of the note, that the original note was given as a satisfaction of the guaranty, and that plaintiff was suing for both parties. That suit might be brought by plaintiff as payee and holder of the note, even if he did not have the entire interest in it, cannot be doubted. First National Bank v. Hummel, 14 Colo. 259, 23 Pac. 986, 8 L. R. A. 788, 20 Am. St. Rep. 257.
Section 386,8, C. L. 1921, provides that a holder may sue in his own name, and that payment to him in due course discharges the maker.
The cause being tried upon the theory above stated, any evidence supporting the right of action on that theory was competent. Of course, the payee of the note, if not the' owner, could not by suit cut off any defense which the maker might have against the real party in interest. .As the court eventually found and determined the cause upon a finding that the guaranty was that of the company, and not of the defendant, it is evident that the letter was very important evidence for plaintiff. Its rejection was error.
The court erred also in refusing the application to make Williamson a party plaintiff. Since it is not disputed that he was beneficially interested in the note, he was entitled to be made a party plaintiff. First National Bank v. Hummel, supra.
As the judgment must be reversed because of these errors it is not necessary to discuss the other assigned errors. Judgment reversed.
Mr Justice Denison and Mr. Justice Whitford concur.