Intracranial atherosclerosis is a common cause of stroke. Although it has been recognized for decades, the lack of successful treatment strategies has limited clinical interest until recently. We review the natural history and pathophysiology of intracranial atherosclerosis. Vascular biomechanics are important to define differences between cerebral arteries and extracranial vessels and partly explain the technical challenges facing cerebral artery revascularization as compared with revascularization of coronary arteries. Pharmacological interventions to prevent stroke have had limited success, but technological developments offer improved methods for endovascular revascularization of symptomatic and asymptomatic cerebral artery stenosis. Identification of appropriate candidates for treatment also remains a challenge, and our knowledge about the natural history of the disease is limited. At this time, patients with significant intracranial stenosis should receive information on the benefits and risks of revascularization therapy. Determining which patients should undergo revascularization procedures will require carefully planned, randomized clinical trials.