This book is based on the belief that changes in the size, shape, and capability of the human body since the beginning of the eighteenth century both reflect and illuminate economic and demographic change over those three centuries. Such change has been immense. To take the United Kingdom as an example, its population has risen from under 5.5 million in 1700 to over 61 million today; life expectation at birth has risen from about 38 years to 75 years for males and 80 years for women; and gross domestic product per capita has risen in real terms from £1,643 to £20,790 (Wrigley 2004). Despite the setback in the world economy at the time of writing, similar changes have occurred in every other country of the developed world and are now occurring in almost every country in the world as a whole. At the same time, humans have become much taller and heavier and now experience lives which are much healthier, as well as longer, than ever before in human history.

It is only recently that the full potential of linking these apparently disparate aspects of the human experience has been realized by historians, economists, human biologists, and demographers. It was a matter of common observation during the eighteenth and nineteenth centuries that men and women from the richer groups within a given society – be it France, Britain, Belgium, or the United States – tended to be taller and heavier than those from poorer backgrounds, to suffer less from chronic and debilitating diseases, to live as long or longer and to be capable of harder and more sustained work.