The 12 Steps of Alcoholics Anonymous are rooted in the practices of self-examination and surrender to God that were popularized by the Oxford Group, an evangelical Christian movement of the 1930s. The 12 Steps were formally written down and popularized by Bill W., a recovering alcoholic.
Bill W. learned about these principles from his old friend and drinking buddy, Edwin "Ebby" T. Ebby had learned them from his friend Rowland H., who sought out the Oxford Group in his search for a life-changing spiritual experience, which he believed was the only way to help his alcoholism.
In AA's earliest stages, the 12 Steps were practiced informally, and the focus was on meetings and support. However, in 1938, Bill W. and Bob S. decided they should write the steps down for people who could not attend meetings. They based the formal steps on the Oxford Group's major tenets.
From the initial publication, other writers also interpreted and added to the 12 Steps. For example, the 12 Traditions are a common part of AA meetings and were added later. The 12 Steps have also been interpreted in ways to move away from the initial Christian theology they were based on and make them more inclusive to atheists, agnostics and people of other faiths.