Deep brain stimulation (DBS)--a broadly accepted therapeutic modality with tens of thousands of patients currently implanted--is the application of implantable electrical stimulation devices to treat neurological disorders. Approved indications include involuntary movement disorders; investigational applications include epilepsy, selected psychiatric disorders, and other conditions. DBS differs fundamentally from functional electrical stimulation and sensory prosthetics in that DBS therapies do not substitute for or replace injured tissues, organs, or body functions. DBS--targeted to particular brain nuclei or pathways that are specific for the disorder under treatment--influences brain function and behavioral output in ways that can relieve symptoms and improve the overall functioning of the patient. We will briefly review the history and present status of DBS from a technical and device-oriented perspective, with an eye toward future advances.