Book excerpt: Trace Analysis by Mass Spectrometry deals with trace analysis of solids and liquids by mass spectrometric techniques. Topics include the physics and techniques of electrical discharge ion sources, transmission of ions through double focusing mass spectrometers, and detection and measurement of ions by ion-sensitive plates. The ion sources used are principally electrical discharge type sources. This book is comprised of 14 chapters. The first several chapters focus on the basic physics of electrical discharge ion sources, double focusing mass spectrometry, and the measurement of arrays of mass resolved ion beams by electrical detection methods and with ion sensitive emulsions. The discussion then shifts to the problem of obtaining the chemical composition of the recorded mass resolved ion sample and relating this composition to that of the original sample. The chapters that follow describe specific techniques for analyzing special samples such as insulators, powders, microsamples, biological materials, reactive and low melting point substances, radioactive materials, and gases in solids. The remaining chapters include the use of laser ion sources in the analysis of solids and the analysis of surfaces particularly with sputter ion sources. This book will be of interest to students and practitioners of physics and chemistry.