From P2P to Web services and Grids is a new book, which portrays a clear overview of how computers are connected within the next-generation Internet applications. This book illustrates how current technologies in hot-topic areas, such as peer to peer (P2P) and Grid computing, are used in today's applications. Where possible, I've tried to using simple terminology and graphical illustrations to present often difficult-to-grasp technologies to paint a focused, yet comprehensive picture of the recent major advances within distributed computing.

I draw from real examples, ranging from grass roots Internet culture file-sharing applications, such as Napster, Gnutella and Freenet to high-performance applications, which use modern Grid technology to transfer Terabytes of information between cites worldwide. Even these diverse applications have a common goal; that is, to provide a virtual overlay over the existing Internet, which allows users or programmers to see the Internet not as a collection of incompatible devices but as one coherent platform for deploying their applications. The subtitle of the book, "Peers in a Client/Server world", acknowledges this transition from the current client/server based Internet to new and exciting applications which use this overlaying to create their own personalized view of the internet.

Grid technology likens itself to the electrical power Grid, as it wishes to allow users to tap into Internet computing resources as easily as electrical power can be drawn from a wall socket. To make this happen however, the underlying infrastructure would need to be installed in every household and companies would have to agree on what this infrastructure looked like - itself, a formidable task. As Tim Berners-Lee said after he invented the first Web browser, which started the current World Wide Web, "now that was the easy bit, the difficult bit was to get people to join in ...". So, as explained in the text, the Grid computing field is addressing this issue by adopting and conforming to many Internet standards and we are now seeing a convergence between a number of these technologies, such as Grid computing and Web services. Several chapters therefore are dedicated to describing these and related state-of-the-art technologies (e.g. WSDL, SOAP, WSRF, OGSA, UDDI to name a few). P2P, on the other hand focuses other issues, such as decentralisation, scalability and redundancy, and has a culturally different perspective. However, as you will read, the convergence of such technologies is not too far down the line ...