Book excerpt: The Cell Nucleus, Volume III focuses mainly on nucleic acids, nuclear proteins, and special aspects of nuclear functions. This volume particularly discusses the organization of bacterial and viral DNA, as well as the nuclear DNA of eukaryotic organisms. It also describes nuclear DNA polymerases, precursors of messenger RNA, ribonucleoproteins, and nuclear high- and low-molecular-weight RNAs. Furthermore, this volume looks into the two broad classes of nuclear proteins: histones and nonhistone proteins. It also presents advances made in the knowledge of mammalian DNA-dependent RNA polymerase, cytochemical detection of nuclear enzymes, and nuclear protein synthesis. Moreover, it elucidates the effects of female steroid hormones on target cell nuclei, describes the nucleus during avian erythropoiesis, and reports the general properties of intranuclear viruses.