A much-needed guide exploring social protection on poverty, inequality, health, and government finance—from cash transfers to unemployment insurance—in low- and middle-income nations. Over the past several decades, social protection programs that provide financial assistance to the poor and insure against shocks for the vulnerable have become widespread in low- and middle-income countries. These programs can play a critical role in society. For instance, conditional cash transfers support the current generation and reduce the transmission of intergenerational poverty, while pensions prevent the elderly from falling into poverty. In the past, much of the research on safety nets and social insurance has been centered on high-income countries. In recent years, given the changing policy landscape, there has been a new and growing economics literature on social protection systems in low-and middle-income countries. The Handbook of Social Protection takes stock of this literature—to understand what we know about the differing aspects of social protection and to highlight the open questions for research for the future. It delves into the research on social protection programs by bringing together top experts in the field to cover topics from targeting to cash transfers to unemployment insurance.