Over the past 70 years, electroconvulsive therapy (ECT) has been proven to be one of the most effective somatic treatments for mood disorders (Abrams 1992). Although the serendipitous discovery of psychotropic medications such as chlorpromazine and iproniazid in the 1950s revolutionized psychiatric treatment, clinicians and researchers soon recognized the limitations of psychotropic medications and ECT remained an important therapeutic alternative. The continued use of ECT has provided support for ECT-related research, including exploration of clinical indications, techniques to maximize efficacy and minimize toxicity (especially cognitive and cardiac side effects), and therapeutic mechanisms of action. In this chapter, we review the history of ECT, the preclinical and clinical data on the mechanism of action of ECT, and the relevant literature related to efficacy. We also provide practical guidelines for the administration of ECT, including the efficacy of ECT in treating various psychiatric disorders as well as appropriate patient selection, stimulus settings and electrode placement, pretreatment medical evaluation, and management of the patient during acute, continuation, and maintenance courses of ECT. Finally, we outline an overview of some recent developments to treat depression with nonconvulsive stimuli such as transcranial magnetic stimulation (TMS).