(concurring):
I join unreservedly in affirmance of appellant’s conviction1 and, in all respects save one, in Judge Leventhal’s excellent opinion for the court. My sole difficulty is the holding that in some instances the trial judge has latitude to permit counsel to argue to the jury for an adverse inference from the absence of a trial witness without an instruction by the judge to the jury on that score.2 In my view, an instruction explaining the legal principles which set the conditions under which such an inference may be drawn should always accompany leave to counsel to solicit it. That, I think, is a step indispensable to adequate guidance of the jury and, by the same token, to the fulfillment of the jury’s mission.
Instructions have an important and familiar role in the federal jury system. Questions of law, of course, are for the judge, but the resolution of issues of fact in common law cases is for the jury.3 That the facts to be inferred from proven facts is exclusively within the province of the jury is a canon that has long been settled.4 5This allocation of trial functions between judge and jury is influenced, if not commanded, by the jury-trial guaranties of the Constitution.® But although jurors are the sole arbiters of the facts, their determination must be reached under legal standards. And since jurors are untrained in the law, they must look to the judge for identification and comprehension of the legal rules that will enable them to discharge their responsibilities. The judge thus has a duty to instruct them, clearly and fully, on the principles of law that apply to and govern the case on trial.6 The duty, indeed, is even greater, for “it is the judge’s special business to guide the jury by appropriate legal criteria through the maze of facts before it. . ” 7 Manifestly, without proper instructions jurors are apt to flounder through individual conceptions — which understandably may well be misconceptions — of what the applicable law actually is.8
*946Instructions, then, are vital cogs in the federal judicial machinery. On their coverage and caliber depends the integrity of jury verdicts and, in the long run, the worth of the jury system itself. The immediate beneficiaries are, of course, the litigants, and their stake in high quality instructions is obvious. For the very best of reasons, a party is entitled to have the jury instructed on all essential questions of law involved in the ease.9 His is the right of trial by jury, and “[i]t is almost, if not, as important to a [party] to have a jury instructed on the law applicable to his particular case by the judge, who knows the law, as to have a jury of his peers.” 10
The basic considerations demanding instructions elucidating for the jury the legal aspects of the case obtain clearly enough when one party requests the jury to draw an unfavorable inference from his opponent’s failure to produce a witness. That we recognized several terms ago when Gass v. United States 11 was decided. There we laid down two requirements to be observed “when counsel, either for the prosecution or the defense, intends to argue to the jury for an inference to be derived from the absence of a witness. . . .”12 One, which the court’s opinion in the case at bar aptly stresses,13 is that counsel must seek and obtain from the trial judge a ruling confirming the propriety of the argument before it is presented to the jury.14 The other is “that if such argument is to be permitted, an appropriate instruction should be given defining for the jury the conditions under which the inference might be properly drawn.”15 “Only by such a practice,” we declared, “can the risk of vitiating the entire trial by improper argument be avoided, and can the jury be informed sufficiently to enable it to intelligently discharge its function in that regard.” 16
The nub of the matter is that nonproduction of a witness is a circumstance that may or may not offer a contribution to the search for truth at a judicial trial. Numerous American courts — this court included — have struggled in a vast multitude of lawsuits to separate the types of situations wherein the witness’ absence has real significance from those in which it does not. The distillation from these efforts is a fairly complex body of rules by resort to which the fitness of the occasion for jury consideration of an unfavorable inference is to be measured. It takes only brief mention of the leading principles to make evident the need for judges to delineate through instructions to juries the criteria under which the latter may determine whether to draw such an inference in the ease on trial.
The missing witness “inference is based, not on the bare fact that a particular person is not produced as a witness, but on his non-production when it would be natural for [a party] to produce the witness if the facts known by him had been favorable.” 17 It is then, and then only, that nonproduction “serves to indicate, as the most natural inference, that the party fears to do *947so;”18 and it is “this fear [that] is some evidence that the . . . witness if brought would have exposed facts unfavorable to the party.” 19 So it is that “we have carefully restricted application of [the missing witness] rule to situations where it is ‘peculiarly within’ the party’s ‘power to produce’ the witness and where, as well, the witness’ testimony ‘would elucidiate the transaction;’”20 it is, too, why we have “outlawed both comment and instruction as to absent witnesses where either of these conditions was lacking.” 21 And a bundle of subsidiary rules isolate specific circumstances which operate to frustrate satisfaction of one or the other of these requirements and render the inference unavailable.
The whereabouts of the witness may be unknown.22 He may bear such a relationship with one party as to deter the other from calling him23 The witness may be relatively unimportant,24 able only to offer testimony that is cumulative or inferior.25 The witness may be biased against the non-calling party,26 or the testimony anticipated may be privileged.27 A party may have some other satisfactory explanation for non-production.28 The witness, moreover, may be equally available to both parties,29 in which event each may be open to an adverse inference depending for strength upon the surrounding circumstances.30 This catalog is intended to be illustrative rather than exhaustive. And very importantly the missing witness inference is permissive, never mandatory,31 and even when indulged “exerts [only] impeaching [but] not probative force.” 32
Unlike ordinary evidentiary inferences, then, the missing witness inference is not one that jurors can deal with safely by a process of simple deduction from *948the fact that the witness did not appear. It is, rather, an inference the accuracy of which depends upon scrupulous observance of the considerations that might serve to give it validity. In sum, it is of a piece with other inferences that are to be indulged only when special conditions have been met, and are to be utilized only for a limited purpose.33 When lay jurors are not specifically instructed on these topics, counsel’s arguments for an inference can be treacherous.
My colleagues hold that a missing witness instruction by the court should ordinarily accompany authorization of a missing witness argument by counsel, and must invariably do so whenever the trial judge is of the opinion that “the case is clear for a missing witness inference against a party.” 34 They also hold, however, that where the witness is physically available to both parties but “it is debatable which side might more naturally have been expected to call” him, the instruction may be omitted notwithstanding argument for a “ ‘natural’ inference of fact to be drawn.” 35 With all due respect, the latter is a proposition to which I am unable to subscribe.
Solicitation of a missing witness inference without an instruction defining its legal prerequisites36 does not comport with judicial policy favoring juries as well informed about their assigned tasks as is possible.37 The jury’s need for guidance, it seems to me, is much greater when an element pivotal to the inference “is debatable” than when the occasion for considering the inference “is clear.” 38 Beyond that, even when the case is conducive to the drawing of a missing witness inference, the jury may employ it only limitedly — for impeachment but not for probative purposes.39 *949A suitable instruction should not be given, I submit, to insure that the jury understands these aspects of the important business it is about.40
Three factors, my colleagues say, have bearing on a trial judge’s decision to allow a missing witness argument without a missing witness instruction41 The first is the judge’s estimate that the argument will be understood and given proper treatment by the jury without an instruction. I cannot place confidence in any such judgment where the jury is told nothing about its prerogatives or its limitations in that regard. The second factor is the judge’s assessment that the tailoring of an instruction “would be unnecessary and time-consuming.” I do not feel that the amount of time required relieves the judge from his duty to formulate and render ample instructions,42 or that instruction of laymen on their new and unaccustomed responsibilities as jurors is unnecessary. The third factor mentioned is the judge’s conclusion that an instruction might be distracting or even counter-productive. If indeed it may be assumed that in particular instances an instruction on missing witnesses can produce those effects, then surely argument by counsel on that subject will do no less.
My view, in a nutshell, is that the missing witness instruction has an office indispensable in missing witness controversies. It tells jurors what they need to know in order to function intelligently in an area fraught with even more difficulties for laymen than for lawyers. It safeguards, as nearly as anything can, the validity of the result the jury reaches, and thus makes a wholesome and essential contribution to the jury’s quest for truth. I would not risk diminution of the values the missing witness instruction confers by presuming that sometimes the case may be better off without it.
. My concurrence reflects full agreement that under the circumstances the prosecutor’s missing witness argument to the jury was improper but not substantially prejudicial to the rights of the accused.
. Ante p. 943.
. Magenau v. Aetna Freight Lines, 360 U.S. 273, 278, 79 S.Ct. 1184, 3 L.Ed.2d 1224 (1958) ; Byrd v. Blue Ridge Rural Elec. Cooperative, 356 U.S. 525, 537, 78 S.Ct. 893, 2 L.Ed.2d 953 (1958) ; Schaefer v. United States, 251 U.S. 466, 476, 40 S.Ct. 259, 64 L.Ed. 360 (1920) ; Oscanyan v. Arms Co., 103 U.S. 261, 266, 26 L.Ed. 539 (1880).
. E. g., Barreda v. Silsbee, 62 U.S. (21 How.) 146, 166, 16 L.Ed. 86 (1858) ; Nutt v. Minor, 59 U.S. (18 How.) 286, 289, 15 L.Ed. 378 (1855).
. U.S.Const. Amends. VI, VII. See Atlantic & Gulf Stevedores, Inc. v. Ellerman Lines, 369 U.S. 355, 359, 82 S.Ct. 780, 7 L.Ed.2d 798 (1961) ; Byrd v. Blue Ridge Rural Elec. Cooperative, supra note 3, 356 U.S. at 536-537, 78 S.Ct. 893.
. E. g., Delli Paoli v. United States, 352 U.S. 232, 238, 77 S.Ct. 294, 1 L.Ed.2d 278 (1956) ; Pleasants v. Fant, 89 U.S. (22 Wall.) 116, 121-22, 22 L.Ed. 780 (1874). The role of the trial judge when instructing the jury lias been described as a careful exposition of “the principles of law applicable to the case, restricted to [those] matters in issue in such manner as to be readily understood by the mind untrained in the law. The issues must be presented is the most intelligible form, and the principles of evidence suggested wherever possible.” Farley, Instructions to Juries — Their Role in the Judicial Process, 42 Yale L.J. 194, 206 (1932). Stated another way, “[t]he sum total must be addressed to the facts to be found by the jury, in order to enable them better to understand their duty and to prevent them from arriving at wrong conclusions.” Id.
. Bollenbach v. United States, 326 U.S. 607, 613, 66 S.Ct. 402, 405, 90 L.Ed. 350 (1946). See also United States v. Casale Car Leasing, Inc., 385 F.2d 707, 711 (2d Cir. 1967).
. While an accused cannot usually complain of right of the trial judge’s refusal to charge exactly as he requests, he may justifiably complain when the judge, instead of charging the jury on the law expressly, relies on the jury’s ability to *946ascertain it somehow. United States v. DiDonato, 301 F.2d 383, 385 (2d Cir. 1962). See also Screws v. United States, 325 U.S. 91, 107, 65 S.Ct. 1031, 89 L.Ed. 1495 (1944).
. Tatum v. United States, 88 U.S.App.D.C. 386, 389, 190 F.2d 612, 015 (1951). See also Screws v. United States, supra note 8, 325 U.S. at 107, 65 S.Ct. 1031; Thomas v. United States, 151 F.2d 183, 186 (6th Cir. 1945). Cf. Brooke v. United States, 128 U.S.App.D.C. 19, 22, 385 F.2d 279, 282 (1967).
. Williams v. United States, 76 U.S.App.D.C. 299, 301, 131 F.2d 21, 23 (1942).
. 135 U.S.App.D.C, 11, 416 F.2d 767 (1969).
. Id. at 19, 416 F.2d at 775.
. Ante p. 943.
. 135 U.S.App.D.C. at 19, 416 F.2d at 775.
. Id. at 19-20, 416 F.2d at 775-776.
. Id. at 20, 416 F.2d at 776.
. 2 J. Wigmore, Evidence § 286 at 166 (3d ed. 1940).
. Id. § 285 at 162. See also Graves v. United States, 150 U.S. 118, 121, 14 S.Ct. 40, 37 L.Ed. 1021 (1893).
. 2 J. Wigmore, Evidence § 285 at 162 (3d ed. 1940).
. Wynn v. United States, 130 U.S.App. 60, 64, 397 F.2d 621, 625 (1967), quoting Pennewell v. United States, 122 U.S. App.D.C. 332, 333, 352 F.2d 870, 871 (1965).
. Id. (citations omitted).
. E. g., Stewart v. United States, 135 U.S. App.D.C. 274, 279, 418 F.2d 1110, 1115 (1969) (supplemental opinion).
. E. g., Burgess v. United States, 142 U.S.App.D.C. 198, 209, 440 F.2d 226, 237 (1970) .
. Brown v. United States, 134 U.S.App.D.C. 269, 270-271, 414 F.2d 1165, 1166-1167 (1969) ; Morton v. United States, 79 U.S.App.D.C. 329, 332, 147 F.2d 28, 31, cert. denied, 324 U.S. 875, 65 S.Ct. 1015, 89 L.Ed. 1428 (1945). See also 2 J. Wigmore, Evidence § 287 at 168-169 (3d ed. 1940).
. Brown v. United States, supra note 24, 134 U.S.App.D.C. at 270-271 n. 2, 414 F.2d at 1166-1167 n. 2; Morton v. United States, supra note 24, 79 U.S. App.D.C. at 332 n. 11, 147 F.2d at 31 n. 11. See also 2 J. Wigmore, Evidence § 287 at 168-169 (3d ed. 1940).
. Jarrell v. State, 251 Ala. 50, 36 So.2d 336, 441 (1948) ; Sterling v. McKendrick, 134 So.2d 655, 658 (La.App.1961) ; State v. DePaola, 5 N.J. 1, 73 A.2d 564, 574 (1950). See also 2 J. Wigmore, Evidence § 287 at 168-69 (3d ed. 1940).
. E. g., Graves v. United States, supra note 18, 150 U.S. at 121, 14 S.Ct. 40.
. See 2 J. Wigmore, Evidence § 290 at 178 (3d ed. 1940). See also Critzer v. Shegogue, 236 Md. 411, 204 A.2d 180, 185 (1964).
. 2 J.Wigmore, Evidence § 288 at 169 (3d ed. 1940). See ante p. 943 n. 18.
. United States v. Free, 141 U.S.App.D.C. 198, 203, 437 F.2d 631, 636 (1970). See McGuire v. United States, 84 U.S.App. D.C. 64, 65-66, 171 F.2d 136, 137-138 (1948) ; Billeci v. United States, 87 U.S.App.D.C. 274, 278, 184 F.2d 394, 398 (1950). See also Culp v. Repper, 64 App.D.C. 337, 78 F.2d 221 (1935) ; Egan v. United States, 52 App.D.C. 384, 287 F. 958 (1923) ; McClanahan v. United States, 230 F.2d 919 (5th Cir. 1956) ; Johnson v. United States, 291 F.2d 150 (8th Cir. 1961).
. See note 36, infra.
. Burgess v. United States, supra note 23, 142 U.S.App.D.C. at 208, 440 F.2d at 236 (concurring opinion). See the discussion there.
. A ready example is the inference derivable from the possession of recently stolen property. See, e. g., Pendergrast v. United States, 135 U.S.App.D.C. 20, 31-32, 416 F.2d 776, 787-788 (1969). Another is the inference that might flow from the accused’s flight. See, e. g., Austin v. United States, 134 U.S.App.D.C. 259, 414 F.2d 1155 (1969).
. Ante p. 943.
. Ante p. 943. See, however, text supra at note 33.
. Notwithstanding the trial judge’s preliminary assessment on the propriety of an inference, the jury must make the final decision. “ [I] t is the court’s function to determine whether a jury could appropriately deduce from the underlying circumstances the adverse fact sought to bo inferred,” but “it [is] for the jury to say whether the inference actually ought to be drawn in the particular case.” Burgess v. United States, supra note 23, 142 U.S.App.D.C. at 209, 440 F.2d at 237 (concurring opinion). See also text supra at notes 3-5. In the situation my colleagues hypothesize, ante p. 943, the jury, before undertaking an inference, must find (a) that the witness was physically available to both parties; (b) that the witness bore a peculiar relationship to one party; (c) that the witness could have given testimony materially helpful to that party; (d) that, in view of the relationship, that party would naturally have called the witness; (e) that the witness was not called because the party to whom the relationship was borne did not dare do so, and (f) that, all circumstances considered, that fear indicates that if called the testimony of the witness would have been unfavorable to the party. Only if the jury reaches each of these conclusions would an adverse inference become legally proper, and if proper the jury would then have to gauge precisely its impeaching effect. See text supra at note 32 and accompanying-note.
. See text supra- at notes 6-8.
. Ante p. 943. See Cooper v. United States, 123 U.S.App.D.C. 83, 85, 357 F.2d 274, 270 (1966) (concurring opinion), and cases cited in note 1 thereof.
. See text supra at note 32. Our decisions have consistently maintained the trial judge’s duty to mark out the boundaries within which the jury can legitimately consider evidence admitted for only a limited purpose. United States v. McClain, 142 U.S.App.D.C. 213, 217, 440 F.2d 241, 245 (1971) ; Jones v. United States, 128 U.S.App.D.C. 36, 38-39, 385 F.2d 296, 298-299 (1967) ; Coleman v. United States, 125 U.S.App.D.C. 246, 248-249, 371 F.2d 343, 345-346 (1966), cert, denied, 386 U.S. 945, 87 S.Ct. 979, 17 L.Ed.2d 875 (1967) ; Bartley v. United States, 115 U.S.App.D.C. 316, 318-319, 319 F.2d 717, 719-720 (1963) ; Wheeler v. United States, 93 U.S.App.D.C. 159, 166 n. 17, 211 F.2d 19, 26 n. 17 *949(1953) , cert. denied, 347 U.S. 1019, 74 S.Ct. 876, 98 L.Ed. 1140, reh. denied, 348 U.S. 852, 75 S.Ct. 21, 99 L.Ed. 671 (1954) .
. The responsibility for elucidating the applicable law for the jury rests on the trial judge, and that duty cannot be abdicated to counsel’s argument. See Wheeler v. United States, supra note 41, 93 U.S.App.D.C. at 167, 211 F.2d at 27, and cases cited in note 20 thereof.
. Ante p. 944.
. The amount of time the framing of an adequate instruction would require is, I submit, quite small. The judge need only incorporate in the standard missing witness instruction the special elements summoned by the particular situation the court’s opinion speaks to. See note 36, supra.