I did a quick Google search for Lua books and quite a few came up. I'm not sure which ones are good for beginners and which ones are too advanced. Can someone please point out 2 or 3 that would help out a beginning scripter?
Here are some that stood out: http://www.amazon.co.uk/ROBLOX-Lua-Scripting-Douglas-Snipp/dp/1508728313/ref=sr_1_7?ie=UTF8&qid=1444869805&sr=8-7&keywords=Lua
http://www.amazon.co.uk/Basic-ROBLOX-Lua-Programming-Edition/dp/1475026048/ref=pd_sim_sbs_14_1?ie=UTF8&refRID=0R72PDKT79ZH1XDFFKX5&dpID=41xTaPhqXTL&dpSrc=sims&preST=AC_UL160_SR112%2C160
http://www.amazon.co.uk/Intermediate-ROBLOX-Programming-Black-White/dp/0985451327/ref=pd_sim_sbs_14_2?ie=UTF8&refRID=0R72PDKT79ZH1XDFFKX5&dpID=51WOS7QapdL&dpSrc=sims&preST=AC_UL160_SR128%2C160
Thank you.
Here's a book
http://www.lua.org/manual/5.1/manual.html
The whole thing. Roblox uses Lua 5.1, this book is about Lua 5.1. Roblox also has a wiki that you can reference for things that are Roblox-specific.
Books don't change. They don't get updated unless you get another book. Roblox changes. Roblox gets updated every couple weeks. So does the wiki. I don't recommend buying anything.