Duncan J. Watts: Six Degrees
Six Degrees: The Science of a Connected Age; from Eric Bonabeau’s Amazon.com review: “[This] book is the perfect complement to Barabasi’s Linked in two ways: (1) it focuses on small-world networks rather than (mostly) scale-free networks. (2) It focuses on the social and economic sciences – mostly human networks. Six Degrees is deep, accurate and at the same time clear and easy to read.”