Pretty short but clear book on Erlang. The first half consists of things I'm familiar with already (immutability, pattern matching, recursion, higher order functions). It was the last half that I was more interested in, process oriented programming and OTP. I'll have to read a more in depth book to understand it thoroughly, but it's a very interesting approach.

Alan Kay said Erlang is closer to what he meant by object oriented than Java or C++:

computinged.wordpress.com/2010/09/11/moti-asks-objects-never-well-hardly-ever/#comment-3766