Neuronal nicotinic receptors are key molecules for signal transduction in a number of neuronal pathways. They are widely distributed in the brain and are known to be involved in cognitive tasks, including learning and memory, in smoking addiction and in several brain diseases, such as Alzheimers and Parkinsons dementias, schizophrenia, and epilepsy. This book provides a comprehensive review of the field, starting with a historical perspective and dealing with the molecular structure of these receptors, their biophysical and pharmacological properties, their distribution in central and peripheral nervous systems, and their major involvement in brain functions. Particular emphasis is paid to drugs (both new and old) that are useful in the diagnosis and treatment of diseases involving neuronal nicotinic receptors. Finally, the relevance of these receptors in smoking addiction is carefully evaluated, together with future trends and the latest results.