From the Studios’ perspective, the consequences of home VTR recording are the same as if a business had taped the Studios’ works off the air, duplicated the tapes, and sold or rented them to members of the public for home viewing. The distinction is that home VTR users do not record for commercial advantage; the commercial benefit accrues to the manufacturer and distributors of the Betamax. I thus must proceed to discuss whether the manufacturer and distributors can be held contributorily liable if the product they sell is used to infringe.

It is well established that liability for copyright infringement can be imposed on persons other than those who actually carry out the infringing activity. Kalem Co. v. Harper Brothers, 222 U.S. 55, 62-63 (1911); 3 M. Nimmer, Copyright Section 12.04[A] (1983); see Twentieth Century Music Corp. v. Aiken, 422 U.S., at 160, n. 11; Buck v. Jewell-LaSalle Realty Co., 283 U.S. 191, 198 (1931). Although the liability provision of the 1976 Act provides simply that "[anyone] who violates any of the exclusive rights of the copyright owner . . . is an infringer of the copyright," 17 U. S. C. Section 501(a) (1982 ed.), the House and Senate Reports demonstrate that Congress intended to retain judicial doctrines of contributory infringement. 1975 Senate Report 57; 1976 House Report 61. n37

n37 This intent is manifested further by provisions of the 1976 Act that exempt from liability persons who, while not participating directly in any infringing activity, could otherwise be charged with contributory infringement. See Section 108(f)(1) (library not liable "for the unsupervised use of reproducing equipment located on its premises," provided that certain warnings are posted); Section 110(6) ("governmental body" or "nonprofit agricultural or horticultural organization" not liable for infringing performance by concessionaire "in the course of an annual agricultural or horticultural fair or exhibition").

[p.487] The doctrine of contributory copyright infringement, however, is not well defined. One of the few attempts at definition appears in Gershwin Publishing Corp. v. Columbia Artists Management, Inc., 443 F.2d 1159 (CA2 1971). In that case the Second Circuit stated that "one who, with knowledge of the infringing activity, induces, causes or materially contributes to the infringing conduct of another, may be held liable as a ’contributory’ infringer." Id., at 1162 (footnote omitted). While I have no quarrel with this general statement, it does not easily resolve the present case; the District Court and the Court of Appeals, both purporting to apply it, reached diametrically opposite results.

In absolving Sony from liability, the District Court reasoned that Sony had no direct involvement with individual Betamax users, did not participate in any off-the-air copying, and did not know that such copying was an infringement of the Studios’ copyright. 480 F.Supp., at 460. I agree with the Gershwin court that contributory liability may be imposed even when the defendant has no formal control over the infringer. The defendant in Gershwin was a concert promoter operating through local concert associations that it sponsored; it had no formal control over the infringing performers themselves. 443 F.2d, at 1162-1163. See also Twentieth Century Music Corp. v. Aiken, 422 U.S., at 160, n. 11. Moreover, a finding of contributory infringement has never depended on actual knowledge of particular instances of infringement; it is sufficient that the defendant have reason to know that infringement is taking place. 443 F.2d, at 1162; [p.488] see Screen Gems-Columbia Music, Inc. v. Mark-Fi Records, Inc., 256 F.Supp. 399 (SDNY 1966). n38 In the so-called "dance hall" cases, in which questions of contributory infringement arise with some frequency, proprietors of entertainment establishments routinely are held liable for unauthorized performances on their premises, even when they have no knowledge that copyrighted works are being performed. In effect, the proprietors in those cases are charged with constructive knowledge of the performances. n39

n38 In Screen Gems, on which the Gershwin court relied, the court held that liability could be imposed on a shipper of unauthorized "bootleg" records and a radio station that broadcast advertisements of the records, provided they knew or should have known that the records were infringing. The court concluded that the records’ low price and the manner in which the records were marketed could support a finding of "constructive knowledge" even if actual knowledge were not shown.

n39 See, e. g., Famous Music Corp. v. Bay State Harness Horse Racing & Breeding Assn., Inc., 554 F.2d 1213 (CA1 1977); Dreamland Ball Room, Inc. v. Shapiro, Bernstein & Co., 36 F.2d 354 (CA7 1929); M. Witmark & Sons v. Tremont Social & Athletic Club, 188 F.Supp. 787, 790 (Mass. 1960); see also Twentieth Century Music Corp. v. Aiken, 422 U.S. 151, 157 (1975); Buck v. Jewell-LaSalle Realty Co., 283 U.S. 191, 198-199 (1931); 3 M. Nimmer, Copyright Section 12.04[A], p. 12-35 (1983).

Courts have premised liability in these cases on the notion that the defendant had the ability to supervise or control the infringing activities, see, e. g., Shapiro, Bernstein & Co. v. H. L. Green Co., 316 F.2d 304, 307 (CA2 1963); KECA Music, Inc. v. Dingus McGee’s Co., 432 F.Supp. 72, 74 (WD Mo. 1977). This notion, however, is to some extent fictional; the defendant cannot escape liability by instructing the performers not to play copyrighted music, or even by inserting a provision to that effect into the performers’ contract. Famous Music Corp. v. Bay State Harness Horse Racing & Breeding Assn., Inc., 554 F.2d, at 1214-1215; KECA Music, Inc. v. Dingus McGee’s Co., 432 F.Supp., at 75; Shapiro, Bernstein & Co. v. Veltin, 47 F.Supp. 648, 649 (WD La. 1942). Congress expressly rejected a proposal to exempt proprietors from this type of liability under the 1976 Act. See 1975 Senate Report 141-142; 1976 House Report 159-160; 1975 House Hearings 1812-1813 (testimony of Barbara Ringer, Register of Copyrights); id., at 1813 (colloquy between Rep. Pattison and Barbara Ringer).

The Court’s attempt to distinguish these cases on the ground of "control," ante, at 437, is obviously unpersuasive. The direct infringer ordinarily is not employed by the person held liable; instead, he is an independent contractor. Neither is he always an agent of the person held liable; Screen Gems makes this apparent.

[p.489] Nor is it necessary that the defendant be aware that the infringing activity violates the copyright laws. Section 504(c)(2) of the 1976 Act provides for a reduction in statutory damages when an infringer proves he "was not aware and had no reason to believe that his or her acts constituted an infringement of copyright," but the statute establishes no general exemption for those who believe their infringing activities are legal. Moreover, such an exemption would be meaningless in a case such as this, in which prospective relief is sought; once a court has established that the copying at issue is infringement, the defendants are necessarily aware of that fact for the future. It is undisputed in this case that Sony had reason to know the Betamax would be used by some owners to tape copyrighted works off the air. See 480 F.Supp., at 459-460.

The District Court also concluded that Sony had not caused, induced, or contributed materially to any infringing activities of Betamax owners. Id., at 460. In a case of this kind, however, causation can be shown indirectly; it does not depend on evidence that particular Betamax owners relied on particular advertisements. In an analogous case decided just two Terms ago, this Court approved a lower court’s conclusion that liability for contributory trademark infringement could be imposed on a manufacturer who "suggested, even by implication" that a retailer use the manufacturer’s goods to infringe the trademark of another. Inwood Laboratories, Inc. v. Ives Laboratories, Inc., 456 U.S. 844, 851 (1982); see id., at 860 (opinion concurring in result). I think this standard is equally appropriate in the copyright context.

The District Court found that Sony has advertised the Betamax as suitable for off-the-air recording of "favorite shows," "novels for television," and "classic movies," 480 F.Supp., at 436, with no visible warning that such recording [p.490] could constitute copyright infringement. It is only with the aid of the Betamax or some other VTR, that it is possible today for home television viewers to infringe copyright by recording off-the-air. Off-the- air recording is not only a foreseeable use for the Betamax, but indeed is its intended use. Under the circumstances, I agree with the Court of Appeals that if off-the-air recording is an infringement of copyright, Sony has induced and materially contributed to the infringing conduct of Betamax owners. n40

n40 My conclusion respecting contributory infringement does not include the retailer defendants. The District Court found that one of the retailer defendants had assisted in the advertising campaign for the Betamax, but made no other findings respecting their knowledge of the Betamax’s intended uses. I do not agree with the Court of Appeals, at least on this record, that the retailers "are sufficiently engaged in the enterprise to be held accountable," 659 F.2d 963, 976 (1981). In contrast, the advertising agency employed to promote the Betamax was far more actively engaged in the advertising campaign, and petitioners have not argued that the agency’s liability differs in any way from that of Sony Corporation and Sony Corporation of America.

Sony argues that the manufacturer or seller of a product used to infringe is absolved from liability whenever the product can be put to any substantial noninfringing use. Brief for Petitioners 41-42. The District Court so held, borrowing the "staple article of commerce" doctrine governing liability for contributory infringement of patents. See 35 U. S. C. Section 271. n41 This Court today is much less positive. See ante, [p.491] at 440-442. I do not agree that this technical judge- made doctrine of patent law, based in part on considerations irrelevant to the field of copyright, see generally Dawson Chemical Co. v. Rohm & Haas Co., 448 U.S. 176, 187-199 (1980), should be imported wholesale into copyright law. Despite their common constitutional source, see U.S. Const., Art. I, Sect. 8, cl. 8, patent and copyright protections have not developed in a parallel fashion, and this Court in copyright cases in the past has borrowed patent concepts only sparingly. See Bobbs-Merrill Co. v. Straus, 210 U.S. 339, 345-346 (1908).

n41 The "staple article of commerce" doctrine protects those who manufacture products incorporated into or used with patented inventions -- for example, the paper and ink used with patented printing machines, Henry v. A. B. Dick Co., 224 U.S. 1 (1912), or the dry ice used with patented refrigeration systems, Carbice Corp. v. American Patents Corp., 283 U.S. 27 (1931). Because a patent holder has the right to control the use of the patented item as well as its manufacture, see Motion Picture Patents Co. v. Universal Film Mfg. Co., 243 U.S. 502, 509-510 (1917); 35 U. S. C. Section 271(a), such protection for the manufacturer of the incorporated product is necessary to prevent patent holders from extending their monopolies by suppressing competition in unpatented components and supplies suitable for use with the patented item. See Dawson Chemical Co. v. Rohm & Haas Co., 448 U.S. 176, 197-198 (1980). The doctrine of contributory patent infringement has been the subject of attention by the courts and by Congress, see id., at 202-212, and has been codified since 1952, 66 Stat. 792, but was never mentioned during the copyright law revision process as having any relevance to contributory copyright infringement.

I recognize, however, that many of the concerns underlying the "staple article of commerce" doctrine are present in copyright law as well. As the District Court noted, if liability for contributory infringement were imposed on the manufacturer or seller of every product used to infringe -- a typewriter, a camera, a photocopying machine --the "wheels of commerce" would be blocked. 480 F.Supp., at 461; see also Kalem Co. v. Harper Brothers, 222 U.S., at 62.

I therefore conclude that if a significant portion of the product’s use is noninfringing, the manufacturers and sellers cannot be held contributorily liable for the product’s infringing uses. See ante, at 440-441. If virtually all of the product’s use, however, is to infringe, contributory liability may be imposed; if no one would buy the product for noninfringing purposes alone, it is clear that the manufacturer is purposely profiting from the infringement, and that liability is appropriately imposed. In such a case, the copyright owner’s monopoly would not be extended beyond its proper bounds; the manufacturer of such a product contributes to the infringing activities of others and profits directly thereby, while [p.492] providing no benefit to the public sufficient to justify the infringement.

The Court of Appeals concluded that Sony should be held liable for contributory infringement, reasoning that "[videotape] recorders are manufactured, advertised, and sold for the primary purpose of reproducing television programming," and "[virtually] all television programming is copyrighted material." 659 F.2d, at 975. While I agree with the first of these propositions, n42 the second, for me, is problematic. The key question is not the amount of television programming that is copyrighted, but rather the amount of VTR usage that is infringing. n43 Moreover, the parties and their amici have argued vigorously about both the amount of television programming that is covered by copyright and the amount for which permission to copy has been given. The proportion of VTR recording that is infringing is ultimately a question of fact, n44 and the District Court specifically declined to make [p.493] findings on the "percentage of legal versus illegal home-use recording." 480 F.Supp., at 468. In light of my view of the law, resolution of this factual question is essential. I therefore would remand the case for further consideration of this by the District Court.

n42 Although VTR’s also may be used to watch prerecorded video cassettes and to make home motion pictures, these uses do not require a tuner such as the Betamax contains. See n. 1, supra. The Studios do not object to Sony’s sale of VTR’s without tuners. Brief for Respondents 5, n. 9. In considering the noninfringing uses of the Betamax, therefore, those uses that would remain possible without the Betamax’s built-in tuner should not be taken into account.

n43 Noninfringing uses would include, for example, recording works that are not protected by copyright, recording works that have entered the public domain, recording with permission of the copyright owner, and, of course, any recording that qualifies as fair use. See, e. g., Bruzzone v. Miller Brewing Co., 202 USPQ 809 (ND Cal. 1979) (use of home VTR for market research studies).

n44 Sony asserts that much or most television broadcasting is available for home recording because (1) no copyright owner other than the Studios has brought an infringement action, and (2) much televised material is ineligible for copyright protection because videotapes of the broadcasts are not kept. The first of these assertions is irrelevant; Sony’s liability does not turn on the fact that only two copyright owners thus far have brought suit. The amount of infringing use must be determined through consideration of the television market as a whole. Sony’s second assertion is based on a faulty premise; the Copyright Office permits audiovisual works transmitted by television to be registered by deposit of sample frames plus a description of the work. See 37 CFR Sections 202.20(c)(2)(ii) and 202.21(g) (1983). Moreover, although an infringement action cannot be brought unless the work is registered, 17 U. S. C. Section 411(a) (1982 ed.), registration is not a condition of copyright protection. Section 408(a). Copying an unregistered work still may be infringement. Cf. Section 506(a) (liability for criminal copyright infringement; not conditioned on prior registration).