Chapter 1. The Facts of Economic Growth Why are people in the richest countries of the world so much richer today than 100 years ago And why are some countries so much richer than others Questions such as these define the field of economic growth. This paper documents the facts that underlie these questions. How much richer are we today than 100 years ago and how large are the income gaps between countries The purpose of the paper is to provide an encyclopedia of the fundamental facts of economic growth upon which our theories are built gathering them together in one place and updating them with the latest available data.