Unlike most of the topics treated in this and in the first volume of the Survey, the problem of economic growth lacks any organized and generally known body of doctrine whose recent development might furnish the subject of this essay. In spite of a continuing interest which began very early, the question has remained on the periphery of economics. But having said so much one must add that some individuals and schools of the nineteenth and the early twentieth centuries gave some aspects of the problem close attention. Adam Smith, Ricardo, and J. S. Mill analyzed the effects of different kinds of progress on the distribution of incomes and speculated about the emergence of a stationary state. The German historians, the American institutionalists, and Marx and his followers studied the appearance and possible decline of capitalist institutions. Weber, Tawney, Veblen, Mitchell and, more recently, Schumpeter explained the development of the mental attitudes that fostered the growth of science and its application to industry. The theory of capital and saving, as developed by the classical and neoclassical economists, has obvious relevance to a theory of long-term economic change, and so has all the work on population theory and the long-run supply curve of labor. Orthodox economics has also furnished us with theories of diminishing and increasing returns that clearly have their place in any general explanation of economic growth. Meanwhile, economic history generally, and statistical work on secular trends in particular, has furnished some of the information so badly needed.