The emphasis is upbeat in this primer on the heart and how to care for it. Doctor Kezdi explains coronary structure and function with the usual impressive numbers on how much blood is pumped per minute. . . day. . . lifetime. He discusses the major heart ailments and treatments and is especially good in explaining the roles of cholesterol and cigarette smoking acting alone or in concert as risk factors in plaque formation. Much of the book is ""Your Heart and. . ."" (sex, heredity, work, environment, etc.) or ""How to. . . (choose a wise diet, relax, quit smoking, exercise. . .). Kezdi appears to be a great believer in self-determination. You can minimize any hereditary predispositions to heart trouble by adopting a wise life style and even live pleasurably following a heart attack. Good advice, earnestly and simply expressed--and undoubtedly of value even if it only serves to restrain a little those of us who like buttered mashed potatoes and martinis before dinner.