When a young man enters Bloomingdale's and loiters for 22 seconds at the makeup counter before moving to the men's department to buy an necktie, Underhill and his researchers are there, recording every pause, facial expression, and sigh. Why? Because Underhill has mastered the science of shopping. There's a lot to learn from his findings, which go beyond the calculations of any state-of-the-art computer programs or costly focus groups to teach you the true nuances of the customer retail experience.