合理使用
Clapp's 1962 work focused on the inherent problem for libraries in reliance upon the copyright fair use exception in the common law, since "Fair use has no statutory basis ... [and] since there is no way of predicting what a court might deem absurd, it is impossible to give a satisfactory definition of what constitutes fair use." Clapp explained that the "Gentlemen's Agreement of 1935" (see Robert C. Binkley: Joint Committee and Documentary Reproduction) between librarians book publishers that, while asserting that publishers maintained absolute right over copyright material, provided a liability exemption for "a single photographic reproduction or reduction of a part of a book or periodical volume in lieu of loan or manual transcription, solely for purposes of research." Clapp referenced the 1961 report to the House Judiciary Committee from the Register of Copyrights that called for statutory resolution to the issue. The report reflected Clapp's views on the need for statutory definition of fair use.