An examination of why humans crave excitement and why excitement has value for both the individual and the culture. The curious behavior of race-car drivers, mountain climbers, stuntmen, and others who seem bent on self-destruction is always a subject of interest to less adventurous observers. But, as Apter (Psychology/Northwestern Univ.) points out, there hasn't been much serious investigation of the motives of risk-takers. Apter kicks off with a discussion of physiological arousal, that network of feelings frequently characterized as ``fight or flight.'' Arousal, he says, can generate feelings of anxiety ranging from apprehension (a visit to the dentist) to panic; it can also generate positive feelings of excitement ranging from titillation to ecstasy. It's the ``protective frame''--the cage that contains the tiger (in the author's most apt metaphor)--that differentiates excitement from anxiety. The meat of the book is in Apter's exploration of those frames, and of how individuals use and misuse them in efforts to promote excitement or to avoid anxiety. The author claims to part company from earlier researchers on ``sensation seeking,'' who describe individual tendencies to seek or avoid arousal as relatively fixed. Everyone rides the tiger to some extent, says Apter, and they move from arousal-seeking to arousal-avoidance many times during each day. Apter also examines war, violence, sex, and creativity as offshoots of the search for excitement. Noteworthy, too, is his eye-opening analysis of the pathology of boredom. Intriguing but--particularly in Apter's reinterpretation of data regarding sensation-seeking--not wholly convincing.