Molecular Mechanisms of Protein Biosynthesis is a collection of papers dealing with cell-free systems at the molecular level, including transfer RNA; the initiation, elongation, and termination processes; ribosome structure and function; mRNA translation; and DNA-directed in vitro protein synthesis. A couple of papers review tRNA, aminoacyl-tRNA synthetases, and aspects of ribosome structure. One paper discusses affinity labeling in the study of binding and catalytic sites of large complex and heterogeneous systems such as the ribosome. The investigator should be aware of the chemically reactive or photoactivatible analogue reacting specifically with one or more ribosomal components. This reaction should be determined if it is dependent on the correct binding of the affinity label at the functional site. Another paper describes the series of reactions in protein synthesis as the process by which the ribosome moves relative to the messenger RNA. Other papers discuss messenger RNA and its translation, DNA-dependent cell-free protein synthesis, as well as the genetics of the translational apparatus. The collection will benefit microbiologists, biotechnologists, and academicians connected with the biological sciences.