Ierusalimschy, Roberto. Programming in Lua, 4th edition. Lua.Org, 2016.

ISBN13: 9788590379867

Programming in Lua (PIL) is written by the creators of Lua. The book takes an example-based approach to teaching—many of the non trivial concepts in the book are explained with real world code samples. The first edition of Programming in Lua is available online, for free.