Linked + Six Degrees - two books on networks
Titles: Linked: How Everything Is Connected to Everything Else and What It Means for Business, Science, and Everyday Life
Authors: Albert-Lászlo Barabási (Linked) and Duncan Watts (Six Degrees)
Genre: Popular Science/sociology/networks
Readability: Linked is very easy to digest, Six Degrees is at times more academic.
Two recent books I have read about the emerging science of networks, as it is applied to areas such as social networks and the diffusion of ideas, the spread of AIDS and other epidemics, and the structure of the internet.
Linked
Watt's Six Degrees
Buying both books doesn't make sense, so if you are interested, go with Linked unless you are curious about mathematical modelling.