This assembly of lectures, each on a major aspect of the development of biochemistry, should appeal to anyone with an interest in the history of science and the nature of living things. Seven of the eight lectures are by eminent biochemists and describe the development of their own subject from the inside; the eighth is a more general one by a professional historian of science. They contain a good deal of information not readily available elsewhere and do not require a special knowledge of biochemistry. The lectures were originally given as a series, over a period of several years, under the auspices of the department of the History and Philosophy of Science in the University of Cambridge.