A reference on cellular signaling processes, the third edition of Signal Transduction continues in the tradition of previous editions, in providing a historical overview of how the concept of stimulus-response coupling arose in the early twentieth century and shaped our current understanding of the action of hormones, cytokines, neurotransmitters, growth factors and adhesion molecules. In a new chapter, an introduction to signal transduction, the book provides a concise overview of receptor mechanisms, from receptor – ligand interactions to post-translational modifications operational in the process of bringing about cellular changes. The phosphorylation process, from bacteria to men, is discussed in detail. Signal transduction third edition further elaborates on diverse signaling cascades within particular contexts such as muscle contraction, innate and adaptive immunity, glucose metabolism, regulation of appetite, oncogenic transformation and cell fate decision during development or in stem cell niches. The subjects have been enriched with descriptions of the relevant anatomical, histological, physiological or pathological condition.