AA has an estimated worldwide membership of 2 million and thousands of meetings in communities everywhere. This massive, life-changing movement had an obscure beginning - a 1935 encounter at a church group between a New York stockbroker named Bill Wilson (henceforth known as Bill W.) and an Ohio surgeon named Bob Smith (Dr. Bob).

After Bill W. began to confront his own addiction, he became convinced that his sobriety hinged on helping others to stay sober. He began working with Dr. Bob, who took his last drink one month later.

The two created the 12-step program that is AA's road map to sobriety. With two other AA pioneers, John Henry Fitzhugh Mayo and James Burwell, in 1939 Dr. Bob wrote "Alcoholics Anonymous," known in AA as "The Big Book."

The AA program is both simple and demanding. It directs people to acknowledge their powerlessness over alcohol, to turn to a higher power - and then to follow a series of steps that include self-searching, making confessions and amends, and reaching out to other alcoholics.

A key reason for the program's remarkable success is that alcoholics can walk into any meeting anywhere - from Eugene to Nairobi - and find people struggling with the same steps, clinging to the same core principles. Differences in race, class and religion melt away in the face of shared struggle and purpose.

As they say in AA, it's just a matter of "one drunk helping another."

The program has its share of critics. Some dislike AA's emphasis on spirituality and say the concept of the sufferer's "personal incapability" conflicts with accepted principles of psychotherapy. Others find fault with AA's contention that addiction is an incurable disease and that sobriety depends in part on long-term involvement with AA. That, they argue, exchanges an addiction to alcohol for an addiction to an organization.

AA members concede their program isn't for everyone. As they say at the end of meetings, they "keep coming back" because, simply and miraculously, "It works."