This edition of the Pension Reform Primer examines the global trend in early retirement among rich and poorer countries, the reasons for people retiring early, the burden of early retirement on the pension system, recent policy initiatives to promote employment of older workers, and people's responses to incentives. The paper notes there is a clear relationship between early retirement and incentives in the pension system, a result confirmed by other international studies and by more detailed econometric analysis of individual countries' systems. It finds that retirement depends on many other factors, such as individual health or the level of unemployment. But financial incentives in the tax and pension system have important effects on the retirement deciosion.