Book excerpt: This new text highlights the value of this biological system as a research and teaching tool. The book is a sequel to the 1983 edition and is organized into 6 major sections: DNA metabolism, regulation of gene expression, morphogenesis, structure of selected proteins, host–phage interactions, and laboratory experiments in T4 molecular genetics. Since T4 has played a central role in the development of molecular biology as an academic discipline, the themes presented in this book provide a framework for designing graduate and undergraduate courses in prokaryotic genetics and biochemistry.