This is a sound introduction to bio-chemistry, that infant science that is making a revolution in our understanding of how our bodies function. This book deals with those "chemicals that control the workings of living tissue" -- the catalysts that make other chemicals function. Many of the questions are still unsolved, but the future answers will be built on the knowledge of those "chemicals of life" described here. While the presentation has somewhat the flavor of text book material, it is text book in the modern sense of direct, undramatized factual data. The audience interested in the subject- and their number is growing wants it that way.