This paper, presented as part of the Lionel Robbins Lectures at the London School of Economics, examines the determinants of economic growth across a panel of around 100 countries from 1960 to 1990. The author, Robert J. Barro, supports the notion of conditional convergence, which posits that for a given starting level of real per capita GDP, higher initial schooling, life expectancy, lower fertility, lower government consumption, better maintenance of the rule of law, lower inflation, and improvements in the terms of trade enhance the growth rate. Conversely, growth is negatively related to the initial level of real per capita GDP. Political freedom has a weak effect on growth but shows a nonlinear relationship, with expansion of political rights stimulating growth at low levels but reducing it once moderate democracy is achieved. The standard of living is strongly positively correlated with the propensity to experience democracy. The paper also discusses the link between inflation/monetary policy and economic growth, finding that higher inflation is associated with lower growth rates. Overall, the empirical findings support the neoclassical growth model and its extensions, highlighting the importance of government policies, human capital, and the diffusion of technology in driving economic growth.This paper, presented as part of the Lionel Robbins Lectures at the London School of Economics, examines the determinants of economic growth across a panel of around 100 countries from 1960 to 1990. The author, Robert J. Barro, supports the notion of conditional convergence, which posits that for a given starting level of real per capita GDP, higher initial schooling, life expectancy, lower fertility, lower government consumption, better maintenance of the rule of law, lower inflation, and improvements in the terms of trade enhance the growth rate. Conversely, growth is negatively related to the initial level of real per capita GDP. Political freedom has a weak effect on growth but shows a nonlinear relationship, with expansion of political rights stimulating growth at low levels but reducing it once moderate democracy is achieved. The standard of living is strongly positively correlated with the propensity to experience democracy. The paper also discusses the link between inflation/monetary policy and economic growth, finding that higher inflation is associated with lower growth rates. Overall, the empirical findings support the neoclassical growth model and its extensions, highlighting the importance of government policies, human capital, and the diffusion of technology in driving economic growth.