"All the King's horses and all the King's mm couldn't put Humpty Dumpty together again." It is entirely possible that the difficulty facing "all the King's men" was principally the lack of a sufficient guide to the techniques of reassembling from a series of small components, the original entity. It is the sincere hope of the editor of the present work and of each of the contributing authors that the modern researcher will not face a similar predicament in his endeavours to reconstruct the complete primary sequence of a protein from the array of component amino acids. Rather, it is the intent that, with this volume, he may proceed untimorously if not with outright confidence toward achieving his purpose. To the newcomer in protein sequencing, compelled by necessity, or fascination, to investigate the exact order of amino acids in proteins, the question of "where to begin" - or "how to do it" is urgent. To those more skilled, a ready source of additional techniques should nevertheless be of value. This volume attempts to present in a single source a discussion of the methods and techniques useful to the determination of the primary structures of proteins and peptides. Hopefully, this book will tell the reader "how to do it".