Actors have proven to be a powerful feature to solve the scaling problem in many commercial sites, Foursquare, LinkedIn, and Twitter to name but a few. Now it has become much easier to understand this valuable capability. Philipp Haller, creator of the Scala Actors, and Frank Sommers have teamed up to bring you a comprehensive introduction to the actor model of concurrency. They show you how to use Scala's actors to build efficient, scalable, and robust concurrent software for the JVM.
Preprint available in ebook format now, and in paper form in February 2011 from Artima [1].
Links:
[1] http://www.artima.com/shop/actors_in_scala