The source form of all the documentation is "Texinfo", which is based on TeX but is like HTML in many ways. Texinfo files are readable text files themselves, and there are tools to translate them into various viewing formats.
The standard distribution comes with documentation in the form of HTML files, which you can look at using your favorite Web browser. You can also print them out using the browser.
The next easiest option is to look at the "info" files, ideally with Emacs so as to get the hypertext abilities, but any other text viewer will do.
For printing, if you can find a preformatted version in PostScript(tm), and have a PostScript printer, then you can send that directly to the printer using `lpr'.
To make a nicely printed manual from the sources, you will need a version of TeX. TeX is widely available.
Note that all the information in the manual is in a portable form, so if you have access to another computer system with a faster or easier-to-use formatting and printing setup, you can use that instead.