The book reconstructs some selected threads in the history of economics, from the classical theory of value elaborated by Smith and Ricardo in the late eighteenth and early nineteenth centuries to the behavioral theory of choice put forward by Kahneman and Tversky in the late twentieth century. Part One illustrates the passage from the classical to the marginal theory of value, which latter emerged in the 1870s. Part Two charts the consolidation of marginalism and developments in utility and demand analysis between the 1870s and 1940. Part Three outlines the history of macroeconomics from the monetary and business cycle theories of the early twentieth century to LucasŐs new classical macroeconomics of the 1970s. Part Four is devoted to the post-1940 history of microeconomics, and examines the emergence of game theory, the axiomatization of utility analysis, the history of expected utility theory, and the challenge of behavioral economics to mainstream economics. The book is addressed to students of economics who acknowledge the wisdom of KeynesŐs claim that Ça study of the history of opinion is a necessary preliminary to the emancipation of the mindČ.