Paxinos and Ashwell's Atlas of the Developing Rat Nervous System, Fourth Edition, builds on the many excellent features of previous editions that have made this book the most cited atlas of the developing rat brain. It provides the most comprehensive depiction of not only the structures in the brain and spinal cord, but also of the peripheral nervous system and target organs that are important for developmental neurobiologists, allowing the user to follow neural structures through the developing embryo in both time and space. The nomenclature and identification of structures in this edition have been thoroughly updated to ensure accuracy and compatibility.