Background: Alcoholics Anonymous (AA) is a worldwide recovery mutual-help organization that continues to arouse controversy. In large part, concerns persist because of AA’s ostensibly quasireligious/spiritual orientation and emphasis. In 1990 the United States’ Institute of Medicine called for more studies on AA’s effectiveness and its mechanisms of behavior change (MOBC) stimulating a flurry of federally funded research. This presentation reviews the religious/spiritual origins of AA and its program and contrasts its theory with findings from this latest science. Method: Literature review, summary, and synthesis of studies examining AA’s MOBC. Results: While AA’s original main text (Alcoholics Anonymous, 1939; 2001; ‘the Big Book’) purports recovery is achieved through quasi-religious/spiritual means (‘spiritual awakening’), findings from studies on MOBC suggest this may be true only for a minority of participants with high addiction severity. AA’s beneficial effects seem to be carried predominantly by social, cognitive, and affective mechanisms. These mechanisms are more aligned with the experiences reported by AA’s own larger and more diverse membership as detailed in its later social, cognitive, and behaviorally-oriented publications (e.g., Living Sober, 1975) written when AA membership numbered more than a million men and women (about half of whom had 5 or more years of sobriety), than with its quasi-religious/spiritually oriented original text (AA, 1939) based on the experience of less than a hundred, very severe, nearly all male individuals, most with short-term sobriety. Conclusions: While the religious overtones of AA continue to raise skepticism and concern in the popular media and scientific arena, evidence now demonstrates AA is an effective clinical and public health ally that aids addiction recovery through its ability to mobilize therapeutic mechanisms similar to those mobilized in formal treatment, but is able to do this for free over the long-term in the communities in which people live. To superficially dismiss AA as a potentially effective addiction recovery support option on the grounds that it is spiritual or religious and therefore unscientific is inconsistent with the body of rigorous research accumulated during the past 25 years.