http://www.amazon.com/Programming-Erlang-Software-Concurrent-World/dp/193435600X
I actually read this book a few years ago. I was searching for a better way for concurrent programming, and found about Erlang, and coincidently, little after Erlang was starting to get some attention. I believe at that time this was the only Erlang book. This book clearly shows and explain how to program in Erlang. Like any other functional programming languages, reading this book was like a wake-up call for me, whose background is mostly OOP and procedural languages. Very enjoyable book.
