I've got one. They are really handy. It's got loads of info including all engine part measurements, clearances, and torque specs to name a few pages. Those books were given to college auto programs that were in the GM program, like my college.
There's also real nice cut away diagrams of the DB2 in there as well as fuel flow diagrams. I remember a few engine cut away diagrams as well as loads of testing procedures. There's too much to list here, but if you can get it for a low price, go for it.
There was also a special much smaller book on the DS4 and another on the Tech II procedures for the 6.5. I have both of those around here somewheres as well, as well as a book for the 7.8L "Duramax" medium/heavy duty truck engine, and an entire book on just T-cases and the IFS 4 wheel drive full of exploded view diagrams.
GM made loads of these books, so any you can get your hands are well worth the read.