This book has a lot of interesting, hard to find information on oil reserves and petroleum geology. Its a must-read for someone interested in the subject of oil depletion. It has some shortcomings though:1-It has a lot of superfluous stuff. For example, there is an interview with a medical doctor on topics quite remote from oil depetion. It was annoying to find this material in the book. But it was easily avoided.2-At times, Campbell didnt stick to the topic. He waders off into simplistic philosphical musings about the meaning of oil depletion. It wasnt helpful.3-An explanation of why oil is only found in special geological formations was not provided. This is a very important aspect to understanding oil depletion.But all things considered, this is a good book to read if you want to understand how much oil is left in the ground, and how much has already one up in smoke.