“Blackout”, a confusing term sometimes denoting amnesia and at other times unconsciousness, has come in the alcoholism literature to designate memory loss associated with drinking alcohol. That alcoholics frequently experience amnesic episodes has been recognized since Bonhoeffer's time, and more recently Jellinek (1952) and others have popularized the notion that blackouts are an important predictor of alcoholism, a conclusion based on questionnaire data indicating that blackouts occur early in the course of alcoholism, well before the appearance of other alcoholic symptoms. Jellinek also believed that alcoholics often had blackouts after ingestion of modest, subintoxicating amounts of alcohol.