I've only read 2 of his books yet, Food combining made easy and Superior Nutrition, but it is good, it makes sense all the way.
You can read a selection of some of his articles here.
A resumé of his good food combining rules.
I think you can listen to lectures of some of his books there, haven't checked yet
Go on RawFoodExplained.com, there is some interesting articles by Shelton :
The Paradise Diet
The Elements of Nutrition
He wasn't selling any products or promoting pills of medecine or artificial vitamins. What he promoted was living foods (fruits, greens, nuts), exercise, rest, sun, pure water, fasting, a peaceful mind... For him, the health is in the body. Diseases come from the outside, like bad foods, who are poisons that intoxicate the body. Good foods are not medecine, they're only supporting the body, by providing only what's essential to maintain an healthy life. To be healthy and to stay healthy, it is useless to ask the scientist or the chimist; one must nourrish himself from all the essential nutrients that Nature offers.
He didn't believe it is possible to be cured with drugs and poisons, like the multi-billionnaire pharmabusiness try to make us believe. He promoted a "drugless healing", by removing the causes of the symptoms, rather than trying to kill the symptoms, which will always reappear if we don't solve the problem at it's source.
Short Biography from wikipedia. This article denigrates Shelton and reduce his life to prison sentences. His life was way more than this, he's the one who contributed the most to hygienism, he's known as "The Father" of the Hygiene movement eventhough he is not the founder of it. The article doesn't say he saved hundreds of lives but mentionned that one or two died, one from an heart attack. How many people die in hospitals ? at least a hundred each day. The whole wikipedia article is from this site, using only the texts about his mistakes, and leaving the exploits he accomplished. I suggest you to read it there then.
This explains why he's been arrested so many times, rarely trialed, kept in jail for many weeks, one time for 10 months, (he always use this to fast and write), it was always " in New York, for "practicing medicine without a licence." The great irony is that Dr. Shelton would never "practice medicine"! Still, that is what the authorities call it when someone tells people how to live, how to sleep, how to eat, and how not to take medicines!"
Notes about the wikipedia article:
"The majority of this article is copied almost verbatim from another site (with the exception of my addendum of Dr. Shelton's cause of death). The article seems to me to be top heavy on Dr. Shelton's personal mistakes rather than accentuating the multitudinous successes which he experienced. Recent scientific discoveries are now demonstrating that Dr, Shelton was WAY ahead of his time. These negative statements made in this Wikipedia article have been distributed in other areas of the Internet which is unfortunate since the art and science of fasting is an invaluable source of healing for many people who have exhausted other medical and alternative therapies for restoration of their health as well as finding relief from PTSD. I feel an overwhelming sense of responsibility in distributing the word that an alternative option exists. I have seen many people who were given the death sentence by the medical profession make a stunning recovery through fasting and these recoveries have been medically documented." - CWatchman on Wikipedia