This book was developed from the proceedings of the first North American Tannin Conference held in Port. Angeles, Washington, August 1988. The objective of the conference was to bring together people with a common interest in condensed tannins and to promote interdisciplinary interactions that will lead to a better understanding of these important substances. Anot. her objective was the publicat. ion of this book because there has not been a monograph devoted to the chemistry and significance of tannins for several decades. The book is organized into sections dealing with the biosynthesis, structure, re actions, complexation with other biopolymers, biological significance, and use of tannins as specialty chemicals. The authors made a special attempt to focus on what we don't know as well as to provide a summary of what we do know in an effort to assist in planning future research. Our thanks go to the authors who so kindly contributed chapters and so pa tiently responded to our requests. We also thank Rylee Geboski and the Conference Assist. ance Staff, College of Forestry, Oregon State University, for their assistance in planning and conducting t. he conference, and Julia Wilson, Debbie Wolfe, Helen Coletka, and Nancy Greene of the Southern Forest Experiment Station, Pineville, Louisiana, who typed the chapt. ers. Linda Chalker-Scott was especially helpful in assisting us wit. h editing. Dick Hemingway is indebted t. o the staff of the Alexandria Forest.