Bash

The Bash webpage has a manual. The current maintainer has a webpage for Bash that includes a FAQ.

Books about the bash shell:

bash Cookbook by Carl Albing, J.P. Vossen, and Cameron Newham (O'Reilly, 2007)
Classic Shell Scripting by Arnold Robbins and Nelson H.F. Beebe (O'Reilly, 2005)
Learning the bash Shell, 3rd Edition by Cameron Newham (O'Reilly, 2005)

Building from source:
(Not necessary but) Bash can be built from its source from the GNU project.