Encouragement to keep an active mind--and exercises for that purpose--by the late author of The Reality of Retirement (1981). Willing spends considerable time theorizing about the mind--which, however, seems to be for him chiefly the seat of ideas (not of aesthetic reactions or feelings). The outlook of the book is consequently somewhat narrow: political involvement is a good thing because it engenders ideas; listening to music, for instance, doesn't figure. But in his general discussion, he does champion some worthy causes: the fact that' mental decline does not inevitably go hand-in-hand with age; the relative rarity of true senility (most cases result from physiological causes and are misdiagnosed by prejudiced physicians). And in his second section, where he applies his precepts, he does offer some interesting projects for those who want to increase their mental acuity: reading aloud to each other; keeping a clipping file of interesting magazine pieces; writing for others (even if it's only letters to the editor); and pitching in with public service broadcasts at local cable TV or radio stations. Plus such standards as keeping a journal of thoughts. A snappy magazine article might have put across the points more serviceably; but this will keep the mind occupied--to advantage.