This is the 4.0.18+ 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 http://www.bugzilla.org/docs/. However, you should read the version which came with the Bugzilla release you are using.
In addition, there are Bugzilla template localization projects in several languages. They may have translated documentation available. If you would like to volunteer to translate the Guide into additional languages, please visit the Bugzilla L10n team page.