This is a great book for engine builders or amature mechanics that are looking into purchasing a new camshaft for their engine. It first starts out by explaining the basics of how a camshaft works and all the terminology that is used. It is very complete in this section and most people would have to read it a few times to understand it. Then it goes into duration of camshafts which tells the reader how to select the right camshaft for their desired operating RPM ranges. I feel that there was almost too much information on this subject for it goes way into the physics of why camshafts build power in these ranges. The plus part of this is that it goes into all types of engines, overhead cams, duel valves, four valves, etc. The most helpful section to me was the checking the camshaft section. It explains how to take an exsisting camshaft and pull it from the engine then inspect it to see if you need a new camshaft or if you can work with what is exsisting, thus saving money! The book then goes into timing principles which help in understanding what goes on but it is a little too simple to derive enough information to time a camshaft in the engine before assemlby and running. But the book then explains many of the problems with camshafts that can be solved, not by the home mechanic...but instead by his/her credit card. The last few chapters go into great detail on timing a camshaft using a degree wheel and by finding TDC using various methods. The final chapter is about testing the engine after its running and in the vehicle. This is a vague chapter as not all of the problems it explains can only be the camshaft, this could be misleading to an amature mechanic. I would definetly recommend this book to anyone building an engine for the first time, or anyone looking to do a camshaft swap into an exsisting engine.