Gladwell's other entry on this list, right behind Blink, is proof that you don't need a Robert Langdon to make a best-selling franchise. The pop sociologist's first book, 2002's The Tipping Point, makes the case that ideas can spread like viruses, passing from a few initial vectors until they reach critical mass and "change the world." As in Blink, Gladwell marshals an impressive array of examples (like teen smoking or New York City crime rates) to prove his point. A master of explaining sociology to laypeople, few other writers can make you feel smarter while flying at 35,000 ft.