This paper examines the third fair use standard in section 107 of the 1976 Copyright Act--"the amount and substantiality of the portion used in relation to the copyrighted work as a whole"--as it applies to copying for extended classroom uses such as library reserve. The guidelines are interpreted in terms of amount, substantiality, public use, and multiples of single copies. The connection of this standard with the "anthologizing" principles outlined in the fair use guidelines and with the "systematic reproduction" provision in section 108, which deals with library and archive exemptions, is also discussed. (8 references) (MES)