The doctor was a Crook
Investigator Rose Fox writes:
Here you will find many of the yeasty books written by Dr. William G. Crook. (Occasional co-authors include Elizabeth B. Crook and Cynthia Crook.)
Dr. Crook’s research on yeast hypersensitivity has been prominently covered on Quackwatch. So apparently he was a quack as well as a Crook.