Photo: Ben Goldstein/Studio D

By Nicholas A. Christakis, MD, PhD
352 pages; Little, Brown

A neighbor's loneliness can make you lonelier. Love at first sight is no accident. Obesity is contagious. "You make me sick" may be a statement of fact. Connected, by Nicholas A. Christakis, MD, PhD, and James H. Fowler, PhD, explores the startling intricacy of social networks—how they're formed, how they influence economic, political, and other behaviors. "Only connect" was E.M. Forster's survival strategy. To which this duo of scientists might answer, As if you had a choice!