Collects the author's best "New Yorker" pieces, including essays on such topics as why there are so many kinds of mustard but only one type of ketchup, a surprising assessment of what makes a safer car, and an examination of a machine built to predict hit movies. Gladwell also explores intelligence tests, ethnic profiling and "hindsight bias," and why it was that everyone in Silicon Valley once tripped over themselves to hire the same college graduate.