By Roberto Ierusalimschy; Lua.org, 2003, ISBN 8590379817. Official book, by Lua's main architect, covers all aspects, from basics to API with C; gives solid base for programmers to use Lua.
Overview from journal, by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar Celes Filho; Software: Practice and Experience, John Wiley and Sons, 1996.
Home site; lightweight, made to extend programs, often used for general-purpose, standalone use; simple procedural syntax, powerful data description constructs use associative arrays, extensible semantics; dynamically typed, bytecode interpreted, garb...