In this widely cited book Kaplan details notions of copyright and its infringement in order to determine the criteria that should determine public policy concerning copyright protection. Invited to give the James S. Carpentier Lectures for 1966 at Columbia University, Professor Kaplan chose the provocative subject of copyright. Although the Copyright Act of 1976 followed these lectures by a decade, they remain highly influential and undoubtedly influenced the authors of the 1976 Act. Lecture I, The First Three Hundred Fifty Years, sketches the evolution of ideas about the ownership of literary, musical and artistic works from their origins in the English censorship of the sixteenth century to the landmark Copyright Act of 1909, which remains effective for copyrighted works created before the 1976 Act went into effect in 1978. Kaplan shows how Classical and Romantic conceptions of authorship and imitation figure in the development of our understanding of copyright, and that judges Mansfield, Eldon, Story and Holmes contributed in important ways to the formulation of doctrines and attitudes regarding copyright protection. In Plagiarism Reexamined, notions of copyrightability and of infringement of copyright are anatomized in a search for the considerations of public policy that do or should underlie copyright protection. As Judge Learned Hand exerted the greatest influence in shaping thought about these problems during the past half century, his opinions are studied at some length in the second lecture. The concluding lecture, Proposals and Prospects, deals with the major suggestions for reform of our copyright law that have emerged from past debates that have entered into the new draft legislation. Some of the proposals revise the age-old formal requirements of the law such as notice of copyright and official registration of works. Other proposals redefine the subject matter of copyright and, with due regard to the constitutional provision regarding copyright, mark anew the line between national and state regulation. Still other proposals seek to resolve hard conflicts between producers and users of copyrighted works. Of major importance here are questions arising out of the revolutionary advances in technology exemplified by photocopying machines and computers; questions of fixing the duration of copyright protection; questions of the advisability of according special treatment to special users, as in the cases of classroom teachers and educational broadcasters. After considering mechanisms for accommodating the law to environmental changes, the lecture speculates about the long-range future of copyright as a social control.