I. Introduction.- II. Models of Individual Unemployment Duration.- II.1 Models of Labor-Leisure Choice.- II.2 Job Search Theory.- III. Hazard Rate Models.- III.1 Single Risk Models.- III.2 Competing Risks Models.- III.3 Parameterization of the Regression Model.- III.4 Unobserved Heterogeneity.- III.5 Survey of Empirical Findings from Hazard Rate Models.- IV. Alternative Approaches for the Analysis of Duration Data.- IV. 1 Time-Series Regression Analysis with Aggregate Data.- IV.2 Structural Job Search Models.- IV.3 Calculation of Individual Reservation Wage Elasticities.- V. Sample Designs and Semi-Parametric Specification.- V.1 Sample Designs for Unemployment Duration.- V.2 Semi-Parametric Specification of Hazard Rate Models.- VI. The Variables.- VI.1 Unemployment Duration.- VI.2 Economic and Demographic Characteristics.- VI.3 Unemployment Benefits and Expected Earnings.- VI.3.1 The German Unemployment Benefits System.- VI.3.2 Conceptual Issues Regarding Benefits and Earnings.- VI.3.3 Sample Information on Unemployment Benefits.- VI.3.4 Estimation of Wage Offer Distributions.- VII. Results of the Hazard Rate Analysis.- VIII. Summary of Main Results and Outlook on Aggregate Unemployment.- Appendix: Sample Means and Standard Errors.- References.