The first edition of this text was written primarily by one of the present authors (HAS), with a chapter on instrumentation contributed by a second (NLA). The volume was well received, and to keep the text up-to-date a second edition was planned. For this second edition, a third author (WEK) was invited, whose background complemented that of the other two. Each of the authors was assigned several chapters as his primary task while the complete manuscript remained the second ary responsibility of all three. It is hoped that this approach has resulted in a work that is even more thorough than the first edition in covering the basic concepts of infrared spectroscopy. NELSON L. ALPERT WILLIAM E. KEISER HERMAN A. SZYMANSKI v PREFACE TO THE FIRST EDITION My experience with the many infrared spectroscopy institutes held at Canisius College and many discussions with both beginners and experienced practitioners in infrared spectroscopy have convinced me that there is a need for an introductory text devoted entirely to infrared spectroscopy, a text which can be utilized even by those who approach this study with only a limited background. This volume sprang from that conviction. It is intended for all who wish to use infrared spec troscopy in research - especially chemists doing structural work - in routine control work, in industrial development, or in medical appli cations or those military applications where it is employed as an analytical tool.