Practical Physics demonstrates the purposive and critical approach that should be made to all experimental work in physics. It does not describe a systematic course of experiments, but is intended as a companion to any undergraduate course of practical work. The text is in three parts. The first deals with the statistical treatment of data, the second with experimental methods, and the third with such essential matters as keeping efficient records, accuracy in calculations, and scientific writing. The text is liberally illustrated with examples and exercises, with solutions to the latter. The new edition includes a treatment of the χ2 distribution, a section on atomic clocks, worked examples based on spreadsheets, and additional exercises. Existing examples and references have been brought up to date. Although intended for undergraduates, Practical Physics has proved of interest to school-students, teachers, and researchers, not only in physics, but also in other branches of science.