Multitasking is all around us: the office worker interrupted by a phone call, the teenager texting while driving, the salesperson chatting while entering an order. When multitasking, the mind juggles all the many tasks we're doing this second, this hour, this week, and tries to perform them together-sometimes with great ease, sometimes with great difficulty. We don't often stop to think about how exactly we accomplish these feats of multitasking great and small. How do we switch from one task to another? What types of multitasking are disruptive, and when are they most disruptive? And...