Cell Signalling presents a carefully structured introduction to this intricate subject, introducing those conserved features which underlie many different extra-and intracellular signalling systems. Starting with an overview of cell signalling, which highlights its importance in many biological systems, the book goes on to explore the key components of extracellular and intracellular signalling mechanisms, before examining how these components come together to create the signalling pathways, which are so crucial to the survival of all living organisms.