Imagine you want to write a book on the history of popcorn but your publisher expects a book on life on Mars; what do you do? you stitch together both topics as best as you can.
This is what happens here; the author obviously wants to write about a crusade in Transylvania in 1500, but readers expect a book on networks. The result is a bad book; it does not convince when speaking about networks and will bore you to death with the Transylvanian adventures of the author's grand-grand-grand-daddy.
The content can be summed up into two sentences: 1. all human activity is bursty (so what, you do not usually answer e-mail at a steady pace over 24hrs) and 2. human behaviour can be predicted becuse it's highly repeated over time (so what again, it's obvious that I usually sleep in my bed at night).