We wish to understand how economic growth works. We start with the history of economic performance over the past 2000 years, working out which countries have enjoyed sustained growth and how they did it. We look at the effects of growth - the good, the bad and the risks - and how the bads can be managed and most of the risks mitigated. Then we pull all the growth mechanisms together so as to extend the conventional theory of economic growth, to explain the causes as well as the results of growth.The extended theory focuses on markets and industries; it shows how new products pull the economy along a continuing growth path. Demand features - product design, marketing, credit and the consumer society - are central to this process. At the same time, supply expansion, from investment and productivity gains, sustains the growing demand as well as increases incomes. In the right conditions, demand and supply come together to generate continuing growth.