The Linux Documentation Project (see http://www.tldp.org/) is a team of volunteers who produce documentation about Linux. The LDP contains HOWTOs, FAQs, and guides, all of which have been published under a free license.
HOWTOs are step-by-step instructions and are intended for end
users, system administrators, and programmers. For example, the
creation of a DHCP server is described in a HOWTO, as well as the
points to be noted, but not how Linux itself is installed. As a
rule, documentation of this kind is kept quite general so it
can be applied to every distribution. The
howto package contains HOWTOs in
ASCII format. Users who prefer HTML should install
FAQs (frequently asked questions) are collections of questions and answers relating to certain problem areas that frequently arise in mailing lists, for example, “What is LDAP?” or “What is a RAID?” Texts in this category are generally quite short.
Guides are documents that can deal with a topic in much greater detail than HOWTOs and FAQs. Examples include kernel programming and network administration. The underlying idea is to provide the reader with detailed information.
Some LDP documentation is also available in other formats, such as PDF, single and multiple HTML pages, PostScript, and as SGML or XML sources. In some cases, there are also translations into different languages.