The rate of technological and human physiological change in the 20th century has been remarkable. Beyond that, a synergy between the improved technology and physiology is more than the simple addition of the two.

In 1890, nearly everyone died on the job, and if they lived long enough not to die on the job, the average age of retirement was 85.

Centuries ago it may have been difficult for pregnant women and their children to get proper nourishment, probably leading to smaller - and therefore shorter-lived - adults.

The rate of technological and human physiological change in the 20th century has been remarkable. Beyond that, a synergy between the improved technology and physiology is more than the simple addition of the two.

The president has very little effect on the economy. If you want to put blame or credit, the main person who influences the business cycle is the head of the Federal Reserve Bank.

Among the current discussions, the impact of new and sophisticated methods in the study of the past occupies an important place. The new 'scientific' or 'cliometric' history-born of the marriage contracted between historical problems and advanced statistical analysis, with economic theory as bridesmaid and the computer as best man-has made tremendous advances in the last generation.

In most, if not quite all, parts of the world, the size, shape and longevity of the human body have changed more substantially, and much more rapidly, during the past three centuries than over many previous millennia.