Transcranial magnectic stimulation (TMS) is a neurological technique for inducing motor movement by direct magnetic stimulation of the brain's motor cortex-while the subject is awake and alert-to measure connectivity and excitability. It depends on the principle of mutual induction (discovered by Michael Faraday in 1831), whereby electrical energy can be converted into magnetic fields, and magnetic fields can be converted into electrical energy. The ability to measure the excitability of the motor cortex in important in neuropsychiatry for several reasons: 1) TMS may prove valuable as a diagnostic tool, because there is increasing evidence of altered motor cortex excitability in several neuropsychiatric disorders. 2) Stimulus parameters (especially stimulus intensity) must be adjusted to the patient's individual motor excitability in repetitive TMS (rTMS) treatment protocols. Therefore, the knowledge of how to measure motor cortex excitability is indispensable. 3) Evidence shows that various rTMS protocols can increase or decrease cortical excitability and thus can be used therapeutically to normalize altered excitability in neuropsychiatry diseases. How did TMS evolve into the techniques used today? How does it fit into the localization debate (the idea that physiological functions are organized into discrete brain regions), now reenergized by the advent of modern neuroimaging tools (PET, SPECT, and MRI)? How does it differ from ECT? For what disorders is TMS effective, and how is this effectiveness measured? What safety concerns are involved? Where is future research headed? For the answers to these questions, readers can now turn to a single source, "Transcranial MagneticStimulation in Neuropsychiatry," In these fascinating chapters rich with illustrations, current clinical researchers describe how-thanks to TMS-they now have elaborate roadmaps of the brain regions putatively involved in specific disorders including movement disorders, epilepsy, major depression, bipolar disorder/mania, anxiety disorders, developmental stuttering and Tourette's syndrome, and schizophrenia. Even with advances in neuroimaging science, much of the adult human brain remains a mystery. "Transcranial Magnetic Stimulation in Neuropsychiatry" helps shed light on the astonishing intricacies of brain function and organization, and as such is a must-read for anyone interested in how the brain works-clinical researchers of brain function, neuroscientists, neurologists, general psychiatrists, neuropsychiatrists, psychologists, and social workers.