The book covers pretty much everything you'd ever need to know. The new edition is 460 pages long, with 20 some articles from coaches like Baxter, Cross, Robert Lunte, and singers like James LaBrie of Dream Theater, Tony Harnell of TNT, Russell Allen of Symphony X and other big time people.
The technique he teaches is based on 3 main exercises, with different variations of them all. The techniques called the Isolation Method, and is definitely the way to build up a huge range, but you gotta commit to it.
You also get the password to his members section/forum. The members section has 8 hours of video I think, and 70+ audio files to help out.
Definitiely work with Baxter though as soon as you get the chance. Hes my favorite vocal coach i've ever found, and knows his stuff better than anyone else ive come across.