In their recent How to Put Anxiety Behind You (p. 738), Nideffer and Sharpe raced through a hectic survey of popular anxiety-reduction techniques. This book is an attempt to endorse certain of these techniques as a means of focusing attention, and though it has a blessedly narrower focus, it does not quite command attention. During an army stint in Japan, Nideffer studied the martial arts for two years before concluding that there had to be a less painful and time-consuming way to develop concentration. Stress research at the University of Rochester convinced him that people can learn to maintain control even in high-pressure situations by ""centering""--which largely involves good, old-fashioned deep breaths and navel contemplation. The first step is testing for self-knowledge--is your attention broad or narrow, internally or externally focused? Progressive relaxation techniques follow, to develop body awareness (pay attention to your ""key muscle groups""; choose either the standing or the sitting version of the approved body position). The third stage of A. C. T. training combines mental rehearsal procedures with a variation on thought stopping: visualize a terrifying visit to the dentist, for example, and (as one part of the rehearsal process) stop, ""center,"" and switch your thoughts to pleasanter things. A mechanical approach that creaks.