This volume contains surveys of the most important topics in economics.

1. Sorting, education, and inequality Raquel Fernandez; 2. Wage equations and education policy Kenneth I. Wolpin; Empirical and theoretical issues in the analysis of education policy: a discussion of the papers by Raquel Fernandez and Kenneth I. Wolpin Costas Meghir; 3. Toward a theory of competition policy Patrick Rey; 4. Identification and estimation of cost functions using observed bid data: an application to electricity markets Frank Wolak; 5. Liquidity, default, and crashes: endogenous contracts in general equilibrium John Geanakoplos; 6. Trading volume Andrew W. Lo; Discussion of papers by John Geanakoplos and by Andrew Lo and Jiang Wang Franklin Allen; 7. Inverse problems and structural econometrics: the example of instrumental variables Jean-Pierre Florens; 8. Endogeneity in nonparametric and semiparametric regression models Richard Blundell; Discussion of papers by Jean-Pierre Florens and by Richard Blundell and James Powell Manuel Arellano.