The four authors teach developmental neurobiology to third and final year undergraduates as part of courses leading to degrees in Neuroscience, Physiology, Medical Biology, and Pharmacology ( over 100 students in total). They also teach on similar themes to MSc and first year PhD students. They have decided to write this book as there is nothing currently available that focuses on this key topic at a size and level suitable for students with diverse backgrounds.? Building Brains describes the main elements of current understanding of the mechanisms that create the nervous system, from its first beginnings to its mature form. The aim of the book is to focus on the major areas in which breakthroughs have been achieved. For other topics readers will be referred elsewhere.? The book explains how cells make key decisions about becoming neural, when to proliferate and when to differentiate or die, what types of neural cells to become, how to connect to each other and how these connection are refined by spontaneous and environmentally-induced activity.