Attempting to put numbers on past economic activity is a deeply fraught exercise, as the author freely admits.

That being said, this is a book full of useful information and striking estimates. I know of no better place to get a genuine feel for the economic history of the last millennia, but particularly the last two centuries. There is something to startle or surprise anyone within these pages. A necessary edition to the library of anyone seriously interested in history.

This book is seemingly a culmination of the painstaking works taken by Angus Maddison for decades. As I liked his previous works such as the Phases of Capitalist Development, so I like this book very much. Of course, the book contains many 'guesstimations' that are unacceptable to today's economists' rigor. This is more so when the author ventures into almost two millenia before 1820, for which he did relatively little work previously. But even here the book apparently provides reasonable figures synthesizing existing evidences with a lucid interpretation, providing illuminating starting points for future studies.