(concurring):
I concur in the decision that, in its present posture, the denial of the motion to *823quash the subpoenas by Chief Judge Edelstein is neither appealable nor the proper subject for a prerogative writ of mandamus. And I have only admiration for most of my brother Friendly’s scholarly opinion. I believe, however, that the majority opinion goes beyond what is necessary for decision. I cannot subscribe to the necessity for its formulation of tests for summoning unwilling expert witnesses who are entire strangers to the issues in the particular lawsuit.
The appellants are in a different position from the ordinary expert who has no personal relationship with the subject matter of the litigation. These appellants were concededly involved both as observers of and as participants in the phenomenal growth of the electronic data processing industry. The parties and the court are entitled to their testimony in general, as Chief Judge Edelstein recognized. If the questioning should go beyond the anticipated scope, I would leave open the right of appeal by these non-party witnesses provided a contempt order, civil or criminal, issues upon refusal to answer.
I respectfully suggest that all that Carter-Wallace, Inc. v. Otte, 474 F.2d 529 (2 Cir. 1972), cert. denied, 412 U.S. 929, 93 S.Ct. 2753, 37 L.Ed.2d 156 (1973), decided was that “[sjince the witnesses involved here had previously testified as to their opinion, it would seem that they could have been subpoenaed to repeat their testimony here.” 474 F.2d at 536. These prior opinions were given on the very issues in the litigation; there was merely a change of party.1 I suppose that once a judge files an opinion, he commits it to posterity. And every reader becomes as qualified as the writer to say what in the opinion was necessary to the decision and what was said obiter. For we are all normally bound by the words as we have written them, just as a scrivener is bound to the objective meaning of words in a contract. I, therefore, feel free to read Carter-Waliace in a limited way.
In the present case, all that the Government seeks by way of opinion testimony is the “prior opinions of appellants from 1960-1972.” Carter-Wallace holds that experts called upon for such “prior opinions” on the issues involved may be required to testify, and this can be read as including unrecorded prior opinions on the issues involved. On my restricted view of the actual holding, Chief Judge Edelstein had the power, in the circumstances, upon the authority of Carter-Walla ce to deny the motion to quash. This view of Carter-Wallace also makes it reconcilable as an exception to a general rule previously stated in this circuit by Judge Hough, noted by Judge Friendly, that “[a]n expert sells his opinion, as counsel sells his services, and he cannot by law be compelled to testify at all, while an attorney may be compelled to serve.” Cheatham Electric Switching Device Co. v. Transit Development Co., 261 F. 792, 796 (2 Cir. 1919).
For the reasons so well stated by Judge Friendly, I agree that the order is not appealable. I also agree that we should reject mandamus as a remedy since the trial judge did not lack power to make this order, and since there. is no precise question of law which can be or need be decided by an advance supervisory ruling as in Schlagenhauf v. Holder, 379 U.S. 104, 85 S.Ct. 234, 13 L.Ed.2d 152 (1964).
In short, I concur in all of the majority opinion save for the general discussion of the expert witness’ alleged “privilege,” which I think is unnecessary to the decision. A rule that experts may be called generally and required to attend, might make the lives of some experts unbearable. With all the public funding presently available, in addition to the private funds available to private litigants, and the consequent expansion of litigation, unwilling experts on school discrimination, environment and psychiatry, for example, as well as surgeons, could be made subject to intermittent call. I am concerned, particularly in view of its eminent authorship, that the majority opin*824ion will be cited as compelling authority on a subject where there is such a dearth of real authority, and where its implications so clearly contradict New York law, see People ex rel. Kraushaar Bros. & Co. v. Thorpe, 296 N.Y. 223, 72 N.E.2d 165 (1947), which we shall probably have to follow in diversity cases. Federal Rules of Evidence 501.
The difficult problems, as I see them, are how to avoid compelling the expert to go to the expense of hiring a lawyer to vindicate his position, and how much the trial judge must decide in advance of requiring the expert to appear and, in Judge Friendly’s words, be “forced to spend a considerable share of his time in the courtroom rather than the operating room.” See Karp v. Cooley, 493 F.2d 408, 424-25 (5 Cir.), cert. denied, 419 U.S. 845, 95 S.Ct. 79, 42 L.Ed.2d 73 (1974). Should the judge, for instance, require a statement by counsel of what testimony he seeks to elicit from the expert before allowing such a subpoena to be deemed properly issued? Can the matter be decided on papers rather than on oral testimony? Must such a subpoena be served sufficiently in advance of trial to permit its resolution before trial begins?
I am afraid that having stated that mandamus was not a proper vehicle for enunciating rules of guidance for the district court, we may have done just that.
I .think the subject needs exploration in a truly adversary context on a case-by-case basis unless the Federal Rules of Evidence can be amended adequately. Thus, while I agree that there is no absolute privilege for experts, we should not try to define the limits of compelling expert testimony beyond the situation here presented. Here the “experts” are presumably to testify regarding facts and concerning their own activities which relate to the very subject matter of the litigation — practices in the electronic data processing industry. Even an absolute rule of exemption for experts would hardly cover this situation. But I hesitate to discuss the problem of experts who are utter strangers to the subject matter of the litigation, for that problem, I respectfully suggest, is not at all involved on this appeal.
. The precise issue, of course, which the court went on to discuss, was the admissibility of prior recorded testimony without the presence of the witness himself.