Molecular Biology of the Cell, Fourth Edition : A Problems Approach is designed to help students appreciate the ways in which experiments and simple calculations can lead to an understanding of how cells work. Chapters are subdivided as in Molecular Biology of the Cell and provide a review of key terms, test for understanding basic concepts, and research-based problems. Chapters 1-8 and 10-18 from Molecular Biology of the Cell are covered in this way. The new edition of A Problems Approach (formerly titled The Problems Book) is completely reorganized and revised to match the Fourth Edition of Molecular Biology of the Cell. Detailed answers are provided in the book for half the problems to help students learn how to analyze experimental observations and draw conclusions from them. Problems without the solution contained in the book are useful for homework assignments and as exam questions. Answers to these problems are provided to instructors upon request.