Why are some of us permanently damaged by personal setbacks or traumatic change while others pull themselves together and plow on, better prepared for future crises? The answer, says Flach in this guide to handling the endemic stresses of modern life, is ""resilience."" Neither denigrate nor ignore the normal disorientation and depression that follow a crisis, says Flach: ""Failure to pass successfully through a stress cycle can leave us crippled."" After ""disruption"" comes ""reintegration,"" as we marshal our problem-solving and emotional resources to adapt to change--which may involve evaluating self-image and life-goals. All this requires resilience, which Flach now believes to be ""at the heart of what we call mental health."" In case histories drawn from his psychiatric practice, he demonstrates how some--usually middle-class people compulsively chewing the bone of family or career problems--have coped. A wife is abandoned for a much younger woman; when her husband returns, she negotiates a commitment to ""a new level of closeness and sharing."" A retired army officer, who had functioned well in the highly structured world of the military, flounders when he tries to manage a motel he has bought; he succeeds after switching to a franchise operation. But serious psychiatric disabilities, Flach says, may be caused by undiagnosed physical problems. For example, he found a periodically institutionalized ""schizophrenic"" patient to have such a narrow range of vision that she could barely comprehend the world around her. Corrective lenses and eye exercises restored her sanity. Flach has finally rounded out the murky thinking of his The Secret Strength of Depression (1975) and Choices (1977) into a coherent theory, presented here with considerable skill.