This handbook presents the basic skills necessary to function in a water or wastewater laboratory. It does not describe how to perform individual tests; rather it explains and illustrates the underlying techniques and principles involved. The emphasis is on correct use of routine equipment and proper laboratory procedures. The book is designed for anyone wishing to acquire an introductory knowledge of the subject, but who has not had formal training in laboratory skills. Considerable effort has gone into making the explanations and illustrations as clear and concise as possible. We have tried to strip away the aura of mystery surrounding laboratory analysis, while still retaining some of the sense of fun which should be part of any learning experience.