From Writing The Big Book, Page 115-116, on anonymity and an early use of the name of the Fellowship:

   [I]t is important to note that even in this first attempt [to write his own story], Bill is already abiding by the principle of anonymity, referring to his wife only as "Mrs. W." Given the amount of shame the associated with alcoholism - a problem the public assumed to be caused by a lack of will power - it is easy to understand why anonymity was quickly adopted as a defensive measure by the early members of the Fellowship. Wilson's use of his last initial here stands as testimony that the principle of anonymity (later appreciated on a much broader level and eventually enshrined in two of A.A.'s Twelve Traditions) was already being respected as an important part of the program of recovery by late 1938. Nor is this an isolated incident of anonymity. One month later, when Bill was writing to Dr. Bob informing him about the work already done on the book, he noted "nearly everyone [here] agrees that we should sign the volume,Alcoholics Anonymous." (To be clear, this is not the suggested title of the book, but rather the way in which the authors would be identified on the title page.) In short, the foundational principle of anonymity was already being practiced to some degree on New York City by the middle of 1938.