Also meant to mention as others noted, how great of a writer he was. I can't even read the garbage Bob Chick or Peter whoever writes. It's boring, lame, and never inspired me in the least. Reading a column or book by Mike Mentzer always was motivating, and thought provoking. Later when in college when I learned about the scientific methodology and the details of theories and hypotheses, Mentzer's writings seemed more important than I had ever considered. Once you learn and understand the scientific method and terms like validity and reliability, Mike's writings stood out as being far superior and science based than any of the pure garbage Arnold had always published. I also found Mike's statement regarding the "science of bodybuilding" having to exist, and even if he was incorrect in his theory, it didn't invalidate that there was a scientifically provable method of best building muscle.
Not that I have anywhere near the knowledge to make a definitive statement, but it's my opinion that Mike would have benefited from better knowledge of drugs and nutrition. Those were the 2 subjects when he wrote about that were almost dismissive. I remember him mentioning steroids being important and that he remembers taking "boat loads" but didn't seem to think any exact combination or amount was responsible for obtaining an ideal build. And his nutrition writings were very simplistic, he used a calorie consumption vs. expenditure explanation in one book where he was basically saying take your caloric needs and add to them to gain mass or subtract to get ripped. Just an observation that he didn't seem to give nearly any attention to detail regarding nutrition or drugs that he did to training.