“Of all the longevity prescriptions offered by the centarians, work was number one. ... In general, centarians disregard advice to take it easy... As discussed earlier, work seems to be a biological necessity. Eighty-nine percent of centarians report having worked...

“Major changes in brain chemistry accompany depression. This is where antidepressant medicines come in. The use of antidepressant medicine for the depressed person is like the use of insulin for a diabetic—it’s an effort to repair a chemical deficiency, and...

“A recent New York Times report on peak performance noted that world-class violinists practice twice as much as nationally acclaimed violinists, who practice twice as much as local violinists. Such a relationship holds for chess masters as well. Directed effort,...