Bill W.
William Griffith Wilson (November 26, 1895 – January 24, 1971), also known as Bill Wilson or Bill W., was the co-founder of Alcoholics Anonymous
Alcoholics Anonymous
Alcoholics Anonymous is an international mutual aid movement which says its "primary purpose is to stay sober and help other alcoholics achieve sobriety." Now claiming more than 2 million members, AA was founded in 1935 by Bill Wilson and Dr. Bob Smith in Akron, Ohio...

 (AA), an international mutual aid fellowship with over two million members belonging to 100,800 groups of alcoholics
Alcoholism is a broad term for problems with alcohol, and is generally used to mean compulsive and uncontrolled consumption of alcoholic beverages, usually to the detriment of the drinker's health, personal relationships, and social standing...

 helping other alcoholics achieve and maintain sobriety
Sobriety is the condition of not having any measurable levels, or effects from, alcohol or other drugs that alter ones mood or behaviors. According to WHO "Lexicon of alcohol and drug terms..." sobriety is continued abstinence from alcohol and psychoactive drug use...

. Following AA's Twelfth Tradition
Twelve Traditions
The Twelve Traditions of twelve-step programs provide guidelines for relationships between the twelve-step groups, members, other groups, the global fellowship, and society at large. Questions of finance, public relations, donations, and purpose are addressed in the Traditions...

 of anonymity, Wilson is commonly known as "Bill W." or "Bill." After Wilson's death in 1971 his full name was included in obituaries.

Wilson's lifelong sobriety began December 11, 1934.