There are plenty of reviews of his books, and biographies of the man.
If a person read only one book on economics, or politics, or philosophy, I would definitely recommend
Small is Beautiful. It will give you plenty to think about, and could make you a better person. It is an inexpensive book, and is an engaging and relatively easy read. However, it is of little practical PO utility in the sense that it won’t help your odds against die-off. His book could be useful toward pursuing a soft landing, but not much of what he addresses is directly actionable by the average Joe. I do wish I could force every politician, businessman, and economist in the world to read it. I definitely recommend you buy it now, and save it for a rainy day. In the meantime to summarize and quote, “Go plant a tree."
Schumacher was aware of coal and oil depletion. From Part II, Chapter 3: $this->bbcode_second_pass_quote('', 'E')very new discovery of oil, or of natural gas … was hailed as a major event which “fundamentally challenged all future prospects,” as if the type of analysis given above [Hubbert-type projection] had not already <i>assumed</i> that enormous new discoveries would be made every year.