In attempting to get quickly up to speed on the oil business for the purpose of participating in a few wells as a (very) small investor, I bought about ten books of various sorts. This is one of them, and has turned out to be the one I refer to the most.
First, let me say that there are two different types of books on drilling for oil/gas. Broadly, they are books that concentrate mainly on the financial and legal structure of oil deals and books that concentrate on where it is and how to get it out of the ground. This book is of the second sort.