In the new edition, the authors have scrutinized every chapter with an eye toward bringing out key concepts and making connections easier to follow. Perennially challenging topics, such as cellular energetics, cell signaling and immunology, have been revised to improve student understanding. Coverage of developmental biology has been streamlined to focus on just those key areas central to cell biology courses. Every figure in the book was reconsidered and, if possible, simplified to highlight key lessons. Revised end-of-chapter materials include new questions, including additional Analyze the Data problems to give students added practice at interpreting experimental evidence. The result is a book that balances currency and experimental focus with attention to clarity, organization, and pedagogy.