For the first time world-leading experts in the area of cellular signaling have joined to the production of a book on Smad signal transduction. Smads are the principal intracellular effectors of TGF-b family members that control numerous cellular responses with critical roles in development and in tissue homeostasis. In a series of 22 cutting-edge chapters forward looking reviews of Smads are provided that cover their discovery, evolution, role in development, mechanism of action and regulation, and how deregulation in Smad signalling contributes to human diseases. Written for an audience with basic understanding of molecular and cell biology, this volume provides an in-depth review of a rapidly developing field and extensive cross-references between chapters are provided. This book will be of particular interest to basic and applied biomedical researchers (students, post-docs or group leaders) with desire to understand the principles of cell-cell communication and mechanisms by which signaling pathways and gene programs control cell proliferation and differentiation, and how this knowledge may come to be applied in the clinic.