This book was written in the context of the daily confrontation with problems in the utilization of polymeric supports for the synthesis of pep tides. Therefore, views and experiences which usually are not mentioned in scientific journals are collected in these pages. The author has deliberately discussed in detail the possible influence of the polymer phase on the varying reaction conditions in the Merrifield synthesis; this aspect is neglected in most publications dealing with peptide synthesis. However, in view of the growing body of information on the chemistry of polymer-supported peptide syntheses, the international readership should regard the author's arguments as open to discussion. I am very much indebted to all of my colleagues with whom I have had the opportunity to cooperate in studying the potential of the Merrifield synthesis. Above all I like to express my gratitude to my teacher, Professor Dr. Theodor Wieland, Heidelberg, for his boundless encouragement and support in my ef­ forts in the field of peptide synthesis, particularly in its polymer phase bound version. Last but not at least I wish to thank Miss Hildegard Leyden. With in­ finite patience and great accuracy she typed the manuscript in addition to her daily duties. The work which influenced this book was performed under the auspices of the Max-Planck-Gesellschaft, of which the financial support is gratefully ac­ knowledged.