In the years before publication, the attention of many learning theorists had returned to the fundamental question of whether there are identifiably different forms of learning. The present volume, originally published in 1977, contains chapters that reassess our basic learning paradigms of the time. They deal with the definitional problems of isolating operant and Pavlovian conditioning, as well as the attempt to analyze the inevitable interactions that follow. These issues are examined in a variety of settings: some authors deal with operant-Pavlovian interactions directly by devising procedures to generate them; others examine operant-Pavlovian interactions by examining their possible contribution to established conditioning paradigms.