Lewin's Essential GENES, Fourth Edition provides a clear and concise overview, as well as up-to-date concepts and techniques in the area of molecular genetics. This text focuses on essential topics, background, and introductory material on the structure and function of genes and genomes and their associated cellular processes. The Fourth Edition is organized into four parts. Part I: Genes and Chromosomes, Part II: DNA Replication and Recombination, Part III: Gene Expression, and Part IV: Gene Regulation. The content of the text has been added and updated to reflect the research advances in many fields, particularly in Chromatin, Eukaryotic Transcription Regulation, and Epigenetics. Each new print copy includes a Navigate 2 Companion Website that features interactive and informative learning resources that gauge understanding and help students study more effectively.