This fully revised and expanded Third Edition of Ionic Channels of Excitable Membranes describes the known channels and their physiological functions, then develops the conceptual background needed to understand their architecture and molecular mechanisms of operation. It includes new chapters on calcium signalling, structural biology, and molecular biology and genomics. Ionic Channels of Excitable Membranes begins with the classical biophysical work of Hodgkin and Huxley, continues with the roles of channels in cellular signaling, then develops the physical and molecular principles needed for explaining permeation, gating, pharmacological modification, and molecular diversity, and ends with a discussion of channel evolution. Ionic Channels of Excitable Membranes is written to be accessible and interesting to life scientists and physical scientists of all kinds. It introduces all the concepts that a graduate student should be aware of but is also effective in advanced undergraduate courses. It has long been the recognised authoritative overview of this field used by all neuroscientists.