This book will be published in 2010 but a complete pre-publication draft is available here. There is a PDF download link for the entire book near the top of the page.

If you enjoyed reading Albert-László Barabási's classic book "Linked: The New Science of Networks" then this new book looks like a great followup. I have not got too far into David Easley's and Jon Kleinberg's new book yet, but the range of topics in this 800 page book looks like it will make a good read.