This book is comprehensive, well written, and accessible. As a biochemist studying complexity and systems biology over the last 6 months, I found it frustrating that there were no decent textbooks on networks. All of Newman's papers are excellent and must reads, but this book takes everything and puts it into once place (there are over 300 citations, so you can read the primary literature referenced if you want). There are sections on different types of networks (social, electrical, biological, etc.), network theory, graph metrics, and then more applied sections on the best computational methodologies to adapt, the best programs to use, models, and simulating events on networks. This is very helpful as most papers dealing with applied networks don't document what software or programming methodologies they use.
I should point out that you need an A Level Maths (or a good grasp of maths if you're willing to learn as you read) to understand the metrics and measures in this book. Some are simple, but some are quite complicated. If you're needing to go into networks then I highly recommend you pick this up as a primer, irrespective of your background. It's very well written and doesn't plonk you right at the deep end. At 700 pages, it isn't thin, but the size of each page is smaller than A4 paper, so it isn't massive.
If you're wondering whether you should buy this or Newman's older book on the structure and dynamics of networks, get this. The older book is just a collection of papers with commentary - a giant literature review. (not that it's bad, but that book does put you in at the deep end)