Instrumentation, often of a highly sophisticated kind, lies behind many of the most interesting aspects of contemporary chemistry. Some techniques - such as NMR - owe their existance to electronic instrumentation; others have been made simpler, more reliable, and more precise. Yet undergraduates reading chemistry often have only the most rudimentary understanding to be performed.This book aims to introduce chemists to some of the building blocks and devices that make up the most important instruments used in industry and research. It is not a book about electronics or about detailed circuit design, though the first chapter reviews the principles. Simple measuring devices are discussed before the introduction of the constituent elements of more complex devices, and emphasis is given to the enhancement of signal-to-noise ratios, which often lies at the heart of some ofthe most demanding measurements in the chemical sciences. This clearly written text will provide a basic understanding of how instrumentation works and thus help chemists use what is available both correctly and effectively.