This book was developed in response to a need in behavioral teratology for a comprehen sive set of reviews of the field's many topics brought together in a single source. This volume represents the first effort to synthesize and integrate research in the field since 1969 when Justin Joffe wrote Prenatal Determinants of Behaviour. Joffe's book became a standard reference for many years, particularly for the experimental design of animal investigations. It has become increasingly evident, however, that some aspects of design once considered inviolate have changed and become part of a more flexible approach. In current research the emphasis is on a set of prioritized, but focused, experimental ques tions rather than on designs which factor all possible variables into every experiment. Also, new design considerations have arisen over the last 15 years, not appreciated when Joffe wrote. Moreover, the sheer volume of new experimental evidence generated since 1969 has increased the content of the field several fold. These considerations made a new review and critical appraisal of the field compelling. The book is divided into four major sections. Part I contains four chapters. These chapters provide discussions of the general principles of behavioral teratogenesis, and information on the historical, governmental, and methodological contexts in which the field operates. The purpose of these chapters is to provide the framework within which the review chapters in the remainder of the book may best be understood.