This 2001 O'Reilly publication goes over the basics and the not-so-basics of P2P networking. It discusses the fundamental concepts in what P2P means and also takes a wide range of real example networks and describes them in a very real context that is easy to understand. As well as the usual suspects of Napster and Gnutella it also looks at other forms of P2P networking, such as Red Rover, a loosely bound network used to anonymously hold documents possibly of a sensitive political nature outside of the countries where simply being found in the possession of a *broken* modem can wind up with execution (Apparently... don't ask me!)

Concepts such as small world networks are also explored, explaining clearly why it's a really bad idea for a file sharing client like gtk-gnutella to come ready set with 100 standard nodes. Explanations are made about the way that, over time, the network's implicitly random qualities will lead it to even out to an impressive average of approximately 4 steps to any machien on the gnutella network (see "six degrees of kevin bacon"! ;-) )

This is, without exception, the only computer textbook I have ever read purely out of interest. I found it in my University library one wet afternoon and couldn't stop reading it. You forget the complex algorithms underneath it all and really get a good grip of whats going on, and you enjoy the journey too.

Buy it!