This is the 2.18.6 version of The Bugzilla Guide. It is so named to match the current version of Bugzilla.
The latest version of this guide can always be found at https://www.bugzilla.org, or checked out via CVS by following the Mozilla CVS instructions and check out the mozilla/webtools/bugzilla/docs/ subtree. However, you should read the version which came with the Bugzilla release you are using.
In addition, there are Bugzilla template localisation projects in the following languages. They may have translated documentation available: Arabic, Belarusian, Bulgarian, Brazilian Portuguese, Chinese, French, German, Italian, Japanese, Korean, Russian and Spanish.
If you would like to volunteer to translate the Guide into additional languages, please contact Dave Miller.