You can download from the table below pdf copies of the User's Guides for GWB Release 12. The GWB Essentials Guide, GWB Command Reference, and GWB Reference Manual pertain to GWB Student Edition, whereas the other three guides pertain to paid versions of the software.
Got wine, beer, canned beans, and a copy of Bethke's Geochemical and Biogeochemical Reaction Modeling.–Facebook post by Aviv B., waiting for Hurricane Sandy
The textbook Geochemical and Biogeochemical Reaction Modeling, published by Cambridge University Press, contains a complete description of the theoretical basis of the GWB calculations as well as a large number of fully worked examples.
Check out the GWB's online resources:
If you would like to have a copy shop print and bind the User's Guides above, you can have them make covers using these Adobe Illustrator-compatible pdf files. Open the files in AI to see crop marks and printer's bleeds. The covers are set up for coil binding.