That is a very helpful manual (but some people find that it takes a while to understand how the material in it is organized).

Here are other helpful manuals:

The Truck Operator's Manual is available online, in reprint, and on DVD/CD-ROM

The Truck Specifications manual/booklet is available from GM (See Tech Tips) and online

The Truck Shop Manual is available online, in reprint, and on DVD/CD-ROM