A thorough appreciation of the cellular, molecular and tissue changes which precede the birth of an animal is a fundamental requirement for understanding normal structural development and also abnormal processes which result in congenital defects. This textbook provides information relevant to many subjects taught in preclinical, paraclinical and clinical years. Early chapters describe and explain sequential events relating to the division, growth and differentiation of cells and to the formation of foetal membranes, implantation and placentation. Succeeding chapters trace the origin, growth, development and maturation of the major body systems. Age determination of the embryo and foetus is reviewed in a single chapter. Genetic, chromosomal and environmental factors which adversely affect pre-natal development are reviewed in the final chapter. A reading list at the end of each chapter offers additional sources of information on the topics discussed. Tables, flow diagrams and numerous hand-drawn illustrations provide information in a form which complements the concepts presented in the text.