If youth is wasted on the young, old age has not been wasted on Garson Kanin. At 66 (hardly old, except for the thesis of his book), he is determined to declare war "on the mindless youth cult that has our time in its grip." The result is ["It Takes a Long Time to Become Young,"] a slight, indignant and often entertaining defense of his belief that should stimulate his contemporaries to take up arms with him against all the societal wrongs done to older persons….

Mr. Kanin fills his battle plan with vignettes of still-active and productive persons in their 70's and 80's, and parallels them with tales of persons who slowly declined after they were forced to retire….

Mr. Kanin scorns a culture that so worships the young that it loses respect for the old. His own family serves as exemplum for his beliefs. He devotes a...