It is difficult to present in print an up-to-date picture on most subjects in the rapidly moving field of biochemistry. It is virtually impossible to do so in the area of protein biosynthesis. Although this book suffers in this respect, it does present a thorough discussion of this highly interesting and rapidly expanding subject. The first section of the book is concerned with the genetic control of protein synthesis. It is shown how a single mutation can cause a small change in a protein molecule, e.g., the replacement of a single amino acid by another. This can mean a change in or a loss of catalytic activity of an enzyme. In the study of the fine structure of the genes and of the chemical nature of the genetic material the one gene-one enzyme concept is developed into the so-called colinearity hypothesis. This hypothesis proposes that the linear arrangement of mutons within the locus responsible for the synthesis of a particular protein can be correlated with the amino acid sequence of that protein, or that the amino acid sequence of a protein is determined by the nucleotide sequence in a corresponding piece of DNA. After this review on genetic control the author turns to the fractionation of cell components and to protein synthesis in isolated fragments and organelles. He further brings up the functions of DNA and RNA in the chemical mechanism of protein biosynthesis. He explains that the experimental evidence points largely to an indirect role of DNA. Then, discussing the role of RNA, he points out the heterogeneity of cellular RNA, shows how at least some fractions are directly involved in protein synthesis and explains how the integrity of at least part of the RNA is necessary for the synthesis of specific proteins. The discussion is concluded by theoretical considerations of RNA as a genetic messenger. Here particularly, one misses the recent developments on messenger-RNA. Then follows a clear explanation of the chemical pathways of protein synthesis in the well-known sequence: amino acid activation, the transfer function of sRNA and the role of the ribosomes. Commendably, the problems in this generally accepted scheme and the scattered pieces of experimental evidence for alternative pathways are also brought in.