It's a detent starters, but if you know how to search on the web, you can find the Helms manual which is much better. The big flaw of Haynes is that if you don't know where to search for a part, the close-up won't help you locate it.
It also won't help you troubleshoot soemthing. For that join a forum or club, and use the book as a reference to do the repair once troubleshooting is done.

I used it for electrical and for such it's fine...