Lua Reference Manual
Lua 5.3 Reference Manual
Lua 5.3: Incompatibilities with the Previous Version
Lua 5.3: The Application Program Interface
PIL: Programming in Lua (first edition)
Archive of the official mailing list in Lua
(Community based) Lua Wiki
Lua official documentation site
Lua Conf videos
Operator precedence in Lua
Table serialization
LuaJIT
LuaJIT is a Just-In-Time Compiler (JIT) for the Lua programming language.
It is compatible with Lua 5.1 version.
LuaJIT Wiki