Documentation and help
- The definitive source of information on LuaTeX is the LuaTeX Reference; the link points to the latest version, documenting latest builds, but can be used for older versions too.
- The previous document reduced to a cheatsheet is also available with the Short Reference.
- TUGboat (communications of the TeX User Group) has featured regular articles on LuaTeX for some years now.
- More can be found in publications by local user groups and conferences.
- The LuaTeX mailing list is frequented by knowledgeable people and questions rarely remain unanswered.
- There is also a list for developpers for very technical things.
- Questions about LuaTeX can also be asked in other TeX-related lists or sites: texhax, comp.text.tex (and similar groups for different languages), or TeX StackExchange.
- The main source on the Lua language is the Lua reference manual; the link here documents version 5.1, currently used by LuaTeX, but version 5.2 is on its way and very probably used by LuaTeX when stable; see the alpha version of the manual for Lua 5.2.
- Programming in Lua, by Lua's chief architect Roberto Ierusalimschy, is available online for version 5.0, quite usable for later versions.
- All this and more can be found on the Lua website.