As the editor of this volume indicates in the foreword, "If the subject matter of teratology today has only vague and ill-defined boundaries, its objectives are crystal clear." This new series admits the central concern as definition of the field of teratology and also recognizes the thoroughly multidisciplinary character. It takes an important step toward providing an annual survey in those diverse disciplines contributory to the problems of teratology. First of the proposed annual volumes, this book contains seven articles, each approximately 25 pages in length: (1) The causes of Down's syndrome, (2) X-chromosome inactivation in mammals, (3) recent advances in etiology of congenital anomalies, (4 ) immunologic aspects of developmental biology, (5) the teratogenic effects of Azo dyes, (6) effects of ionizing radiation on mammalian development, (7) drugs and human malformations. Each review is well written and authoritative, with an appended bibliography citing a significant amount of recent literature.