The mechanics are not that difficult, assuming you're screw apart. The real hang-up comes in if you don't have access to a shock dyno. Simply replacing parts without dyno-testing is, honestly, pointless, as you never really know where you are (and you should always get dyno sheets when you have someone else do the work).

And, if you have access to a shock dyno, you probably don't need a book on how to do it...

This is one of those jobs I always leave to the pro.