From William Schaberg's Writing The Big Book, Page 383-384:

Chapter Twenty

Hank Parkhurst: Managing Editor and "To Employers"  - November 1938 -

Hank Parkhurst may well have been the busiest man in A.A. during the final months of 1938. In addition to being distracted with Ruth Hock, he was trying to sell shares on The One Hundred Men Corporation while continuing to lay the foundations for a national promotion campaign to coincide with the book's release. Adding to all this frantic activity, Hank was also about to write two chapters for the Big Book as well as having taken the job of finding and hiring an editor to review the manuscript once it was completed.

   In early November, with most of Bill's time devoted to writing, Hank assumed the role of managing editor. Both men were aware of their status as amateurs and knew it was essential to find someone with some real writing and publishing experience to edit the manuscript before it went to press. Parkhurst, still unhappy with much of what had been written, may well have thought someone with an impressive enough set of credentials might be able to critique the substance of Bill's writing and steer the book more in the psychological direction that he had in mind. But whether or not this was actually part of Hank's agenda, both men agreed the book needed to be reviewed by a professional and Parkhurst took charge of that phase of the project...

Two Editors Chosen:

... Hank began his search for a professional to review, critique and correct their book. But rather than hiring just one editor, Parkhurst rather quickly decided on two: Thomas H. Uzzell would review the overall format of the book, while Janet M. Blair would more minutely edit the text. Uzzell may have suggested this creative approach. Dividing the editorial responsibilities between himself, a prominent (and expensive) literary critic, and Blair,  qualified but less prestigious {and therefore less costly) text editor, would effectively reduce the overall expense of the editorial work and keep the costs within A.A.'s limited budget.