Dr. Lenore Terr is clinical professor of psychiatry at the medical school of the University of California, San Francisco. She is the author of Too Scared to Cry and Unchained Memories. In this book she notes that, whereas adults give most of their time and energy to work and love, there is another arena that unlocks the door to self-expression: "Play is essential to maturity. It gives us pleasure, a sense of accomplishment, of belonging. It is an opportunity for learning. It reduces our stresses."

In order to make the point of how important this dimension of life is when we are young, Terr looks at the first symbolic forms of play — peekaboo, the mimicry of infants, the pretend games of pre-schoolers, the hobbies of middle childhood, the rough-and-tumble games of eight- and nine-year-olds, play built upon fantasies about aggression or sex, kissing games, and the on-the-edge dares of adolescence. As Robert Fagen has noted: "In a world continuously presenting unique challenges and ambiguity, play prepares [us] for an evolving planet."

Terr includes many examples of adults who have deepened and enriched their lives with play. Of course, overplay can lead to severe problems, such as gambling addiction. The lucky ones, according to the author, are those who are able to relish the playful dimensions of work and love along with imaginative frolicking.