On petitioners' appeal, a divided panel of the Court of Appeals reversed the District Court's order insofar as it required petitioners to bear the cost required for the transfer agent to compile a list of the class members' names and addresses. Sanders v. Levy, 558 F. 2d 636 (CA2 1976).o The majority thought that Eisen IV, which had affirmed Eisen III in pertinent part, required respondents to pay this cost because the identification of class members is an integral step in the process of notifying them. 558 F. 2d, at 642. On F.2d, rehearing en banc, however, the Court of Appeals reversed the panel's decision and affirmed the District Court's order by a vote of seven to three. Id., at 646.10 It thought that Eisen IV did not control this case because respondents might obtain the class members' names and addresses under the costs in the first instance, "without prejudice to the right of this defendant, at the conclusion of the action, to make whatever claim it would be legally entitled to make regarding reimbursement by another party." The court denied the Fund's request that respondents be required to post bond for the identification costs. All three members of the panel agreed that the order allocating the expense of identification was appealable under the collateral-order doctrine of Cohen v. Beneficial Loan Corp., 337 U. S. 541 (1949). 558 F.2d, at 638-639; id., at 643 (Hays, J., dissenting in part). We agree. See Eisen v. Carlisle & Jacquelin (Eisen IV), 417 U. S. 156, 171-172 (1974). The panel also unanimously affirmed the District Court's ruling that the suit could proceed as a class action. 558 F. 2d, at 642-643; id., at 643 (Hays, J., dissenting in part). This issue is not before us. The panel majority also suggested that the Fund should not be required to bear this expense because it, unlike the other petitioners, was not named as a defendant in the class-action portion of this suit. See id., at 640. The Fund itself, which is in the position of a defendant because it ultimately may be liable for any damages that respondents and their class recover, see n. 4, supra, does not argue in this Court that it should not bear the expense because it is not a formal defendant. We therefore do not rely on any distinction that might be drawn between the Fund and the other petitioners in this respect. 10 District Judge Palmieri, the author of the panel majority opinion, did not participate in the rehearing en banc. Opinion of the Court 437 U.S. federal discovery rules, Fed. Rules Civ. Proc. 26-37. The en banc court further held that although Rule 26 (c) protects parties from "undue burden or expense" in complying with discovery requests, the District Court did not abuse its discretion under that Rule in requiring petitioners to bear this expense. 558 F. 2d, at 649–650. By holding that the discovery rules apply to this case, the en banc court brought itself into conflict with the Court of Appeals for the Fifth Circuit, which recently had held: "The time and expense of gathering [class members'] 552 F. 2d 1088, 1102 (1977). In the Fifth Circuit's view, Rule 23 (d), which empowers district courts to enter appropriate orders in the handling of class actions, is the procedural device by which a district court may enlist the aid of a defendant in identifying class members to whom notice must be sent. The Nissan court found it unnecessary to decide whether Eisen IV requires a representative plaintiff always to bear the cost of identifying class members. Since the representative plaintiffs could perform the required search through the defendants' records as readily as the defendants themselves, and since the search had to be performed in order to advance the representative plaintiffs' case, they were required to perform it and thus to bear its cost. See 552 F. 2d, at 1102–1103. We granted certiorari in the instant case to resolve the conflict that thus has arisen and to consider the underlying cost-allocation problems. 434 U. S. 919 (1977). II The issues in this case arise because of the notice requirement of Fed. Rule Civ. Proc. 23 (c)(2), which provides in part: "In any class action maintained under subdivision (b) (3), the court shall direct to the members of the class the best notice practicable under the circumstances, including individual notice to all members who can be identified through reasonable effort." In Eisen IV, the Court held that the plain language of this Rule "requires that individual notice be sent to all class members who can be identified with reasonable effort." 417 U. S., at 177. The Court also found no authority for a district court to hold a preliminary hearing on the merits of a suit in order to decide which party should bear the cost required to prepare and mail the class notice. Id., at 177-178. Instead, it held: "In the absence of any support under Rule 23, [the representative plaintiff's] effort to impose the cost of notice on [defendants] must fail. The usual rule is that a plaintiff must initially bear the cost of notice to the class. . . . Where, as here, the relationship between the parties is truly adversary, the plaintiff must pay for the cost of notice as part of the ordinary burden of financing his own suit." Id., at 178-179. In Eisen IV, the defendants had offered to provide a list of many of the class members' names and addresses at their own expense in the first instance, if the representative plaintiff would prepare and mail individual notice to these class members." Eisen IV therefore did not present issues concerning 11 See App. in Eisen v. Carlisle & Jacquelin, O. T. 1973, No. 73-203, pp. 184-185. either the procedure by which a representative plaintiff might require a defendant to help identify class members, or whether costs may be allocated to the defendant in such a case. The specific holding of Eisen IV is that where a representative plaintiff prepares and mails the class notice himself, he must bear the cost of doing so. The parties in the instant case center much of their argument on the questions whether the discovery rules authorize a district court to order a defendant to help identify the members of a plaintiff class so that individual notice can be sent and, if so, which rule applies in this case. For the reasons stated in Part A below, we hold that Rule 23 (d), not the discovery rules, is the appropriate source of authority for such an order. This conclusion, however, is not dispositive of the cost-allocation question. As we explain in Part B, we think that where a defendant can perform one of the tasks necessary to send notice, such as identification, more efficiently than the representative plaintiff, the district court has discretion to order him to perform the task under Rule 23 (d). In such cases, the district court also has some discretion in allocating the cost of complying with its order. In Part C, however, we conclude that the District Court abused its discretion in this case. A Although respondents' request resembles discovery in that it seeks to obtain information, we are convinced that it more properly is handled under Rule 23 (d). The critical point is that the information is sought to facilitate the sending of notice rather than to define or clarify issues in the case. The general scope of discovery is defined by Fed. Rule Civ. Proc. 26 (b)(1) as follows: "Parties may obtain discovery regarding any matter, not privileged, which is relevant to the subject matter involved in the pending action, whether it relates to the claim or defense of the party seeking discovery or to the claim or defense of any other party, including the existence, description, nature, custody, condition and location of any books, documents, or other tangible things and the identity and location of persons having knowledge of any discoverable matter. It is not ground for objection that the information sought will be inadmissible at the trial if the information sought appears reasonably calculated to lead to the discovery of admissible evidence." The key phrase in this definition-"relevant to the subject matter involved in the pending action"-has been construed broadly to encompass any matter that bears on, or that reasonably could lead to other matter that could bear on, any issue that is or may be in the case. See Hickman v. Taylor, 329 U. S. 495, 501 (1947).12 Consistently with the notice-pleading system established by the Rules, discovery is not limited to issues raised by the pleadings, for discovery itself is designed to help define and clarify the issues. Id., at 500-501. Nor is discovery limited to the merits of a case, for a variety of fact-oriented issues may arise during litigation that are not related to the merits.13 At the same time, "discovery, like all matters of procedure, has ultimate and necessary boundaries." Id., at 507. Dis 12 "[T]he court should and ordinarily does interpret 'relevant' very broadly to mean matter that is relevant to anything that is or may become an issue in the litigation." 4 J. Moore, Federal Practice ¶ 26.56 [1], ,p. 26131 n. 34 (2d ed. 1976). 13 For example, where issues arise as to jurisdiction or venue, discovery is available to ascertain the facts bearing on such issues. See id., 26.56 [6]; Note, The Use of Discovery to Obtain Jurisdictional Facts, 59 Va. L. Rev. 533 (1973). Similarly, discovery often has been used to illuminate issues upon which a district court must pass in deciding whether a suit should proceed as a class action under Rule 23, such as numerosity, common questions, and adequacy of representation. See Annot., Discovery for Purposes of Determining Whether Class Action Requirements Under Rule 23 (a) and (b) of Federal Rules of Civil Procedure Are Satisfied, 24 A. L. R. Fed. 872 (1975). |