The present volume is designed as a practical tutorial survey not only for all those interested in bioinstrumentation and its applications, but also as a text for a one-semester upper-division undergraduate course in instrumentation for bioengineering students. A knowledge of basic physics, basic electronics, and mathematics to elementary linear dif­ ferential equations is assumed. The book is well suited for use as a reference source for all research and clinical workers in the fields of biology, medicine, and the environmental sciences who have an ade­ quate background in the physical sciences. At the University of Wyo­ ming, the text is also used for a course in the interdisciplinary program for graduate study in the neurosciences. The philosophy espoused herein is fundamental system analysis and design, rather than detailed discussion of particular devices produced by commercial manufacturers. Equipment-oriented texts, although initially useful, tend to become obsolete rather rapidly. Basic design and analysis techniques change little with time. Discussion has been limited to devices that have found applications in the biological, environmental, and medical fields. Many transducers used in other disciplines have been omitted. It is not the author's intent to produce a compendium of transducer applications, but rather an introduction to those techniques used in the environmental, biological, and medical sciences.