Biochemistry and Physiology of Plant Hormones is intended primarily as a textbook or major reference for a one-term ;intermediate-Ievel or ad vanced course dealing with hormonal regulation of growth and develop ment of seed plants for students majoring in biology, botany, and applied botany fields such as agronomy, forestry, and horticulture. Additionally, it should be useful to others who wish to become familiar with the topic in relation to their principal student or professional interests in related fields. It is assumed that readers will have a background in fundamental biology, plant physiology, and biochemistry. The dominant objective of Biochemistry and Physiology of Plant Hor mones is to summarize, in a reasonably balanced and comprehensive way, the current state of our fundamental knowledge regarding the major kinds of hormones and the phytochrome pigment system. Written pri marily for students rather than researchers, the book is purposely brief. Biochemical aspects have been given priority intentionally, somewhat at the expense of physiological considerations. There are extensive citations ofthe literature-both old and recent-but, it is hoped, not so much docu mentation as to make the book difficult to read. The specific choices of publications to cite and illustrations to present were made for different reasons, often to illustrate historical development, sometimes to illustrate ideas that later proved invalid, occasionally to exemplify conflicting hy potheses, and most often to illustrate the current state of our knowledge about hormonal phenomena.