The Schwarzbein Principle. And the author's page is online. Book Two is more about the author's personal own personal experience with her own recommendations, so it includes most of the substance of Book One along with some new material.
I think I kept this book on my shelves because the basic principles are sensible (overview and more details here). The author is an endocrinologist who noticed that her Type II diabetic patients were not responding well to a low-fat, high-carb diet, which was the standard recommendation of the time. So the book is a kind of diagnostic and treatment plan depending on the results of the diagnosis. For insulin-resistant overweight people, she found that a high-protein, moderate fat and low-glycemic carb/vegetable diet had much better results.
At the time I read this book I was having blood sugar swings and as a result trying to eat a high-protein/low carb diet. It did help a lot. But I realized while reading the book that I wasn't really as hypoglycemic as I had thought. Part of my problem was not getting enough exercise, while another part was over-eating simple carbs. Nowadays I can get by with much smaller amounts of protein, though still well in line with the recommendations for a woman of my age.
The book looked suspicious to me at first sight because of its subtitle: "A Regeneration Process to Prevent and Reverse Accelerated Aging". And a few of its recommendations came across to me as at the least, too heavy-duty for my particular issues. For example, she believes that many people have done semi-permanent damage to their hormonal system through their food choices. For this reason, she strongly recommends Hormone Replacement Therapy for some people who aren't responding just to diet and exercise changes. This would be something you would obviously have to do under the supervision of a doctor. (There is a discussion of metabolic types here and the book goes into much more detail --there is a quiz you can take online).
I haven't really read about her science being questioned though some reviews I've read say that her endocrinology focus makes her see everything through that lens.