This volume presents a broad yet detailed review of current knowledge of muscarinic receptors. It describes the detailed insights that have been obtained on the structure, function, and cell biology of muscarinic receptors. This volume also describes physiological analyses of muscarinic receptors and their roles in regulating the function of the brain and of a variety of peripheral tissues. This volume shows how the study of muscarinic receptors continues to provide new and surprising insights not just to the cholinergic system but to the broad areas of neurobiology, cell biology, pharmacology, and therapeutics.