This book explores how persistent states of underdevelopment can arise in strategic environments in which players are imitative rather than fully rational. Standard growth theory teaches that poverty traps are stable, low-level balanced growth paths to which economies gravitate due to adverse initial conditions or poor equilibrium selection. In other words, societies fail to take off into sustained growth because they started out as poor, with, for example, low longevity or poor human capital, or because they cannot invent institutions that successfully coordinate their investments. Evolutionary Games and Poverty Traps explains this pernicious form of coordination failure as a game between economic agents, such as, for example, firms investing in research and development and workers investing in human capital. Rates of return on research and development depend on average human capital, and rates of return on human capital depend on aggregate research and development spending. The outcome is a self-confirming equilibrium in evolutionary stable strategies in which unsuccessful players imitate successful ones. This equilibrium is particularly interesting in that in poor economies with a large fraction of low-human-capital workers or low research and development firms, imitative strategies do not support a take-off into sustained growth. To achieve such a take-off, society should subsidize the cost of education or research and development until the economy builds a critical mass of human capital or research and development.