Plant hormones playa crucial role in controlling the way in which plants grow and develop. While metabolism provides the power and building blocks for plant life it is the hormones that regulate the speed of growth of the individual parts and integrate these parts to produce the form that we recognize as a plant. In addition, they playa controlling role in the processes of reproduction. This book is a description of these natural chemicals: how they are synthesized and metabolized; how they work; how we measure them; and a description of some of the roles they play in regulating plant growth and development. This is not a conference proceedings but a selected collection of newly written, integrated, illustrated reviews describing our knowledge of plant hormones and the experimental work which is the foundation of this knowledge. The information in these pages is directed at advanced students and professionals in the plant sciences: botanists, biochemists, molecular biologists, or those in the horticultural, agricultural and forestry sciences. It is intended that the book should serve as a text and guide to the literature for graduate level courses in the plant hormones, or as a part of courses in plant or comparative development. Scientists in other disciplines who wish to know more about the plant hormones and their role in plants should also find this volume invaluable It is hoped that anyone with a reasonable scientific background can find valuable information in this book expounded in an understandable fashion.