Contents: Robert J. Mislevy, Introduction. J.R. Frederiksen, B. White, Intelligent Tutors as Intelligent Testers. J.R. Anderson, Analysis of Student Performance With the LISP Tutor. D.E. Kieras, The Role of Cognitive Simulation Models in the Development of Advanced Training and Testing Systems. A. Collins, Reformulating Testing to Measure Learning and Thinking: Comments on Chapters 1, 2, and 3. C.S. Gadd, H.E. Pople, Jr., Evidence From Internal Medicine Teaching Rounds of the Multiple Roles of Diagnosis in the Transmission and Testing of Medical Expertise. R.S. Siegler, J. Campbell, Diagnosing Individual Differences in Strategy Choice Procedures. J.C. Campione, A.L. Brown, Guided Learning and Transfer: Implications for Approaches to Assessment. S.P. Gott, The Assisted Learning of Strategic Skills: Comments on Chapters 5, 6, and 7. J.A. Reggia, C.L. D'Autrechy, Parsimonious Covering Theory in Cognitive Diagnosis and Adaptive Instruction. P. Langley, J. Wogulis, S. Ohlsson, Rules and Principles in Cognitive Diagnosis. S. Ohlsson, Trace Analysis and Spatial Reasoning: An Example of Intensive Cognitive Diagnosis and Its Implications for Testing. J. Wesley Regian, W. Schneider, Assessment Procedures for Predicting and Optimizing Skill Acquisition After Extensive Practice. A. Lesgold, S. Lajoie, D. Logan, G. Eggan, Applying Cognitive Task Analysis and Research Methods to Assessment. C.H. Frederiksen, A. Breuleux, Monitoring Cognitive Processing in Semantically Complex Domains. J.M. Orasanu, Diagnostic Approaches to Learning: Measuring What, How, and How Much: Comments on Chapters 12, 13, and 14. S. Embretson, Diagnostic Testing by Measuring Learning Processes: Psychometric Considerations for Dynamic Testing. S.P. Marshall, Generating Good Items for Diagnostic Tests. K.K. Tatsuoka, Toward an Integration of Item-Response Theory and Cognitive Error Diagnosis. R.L. Linn, Diagnostic Testing: Comments on Chapters 16, 17, and 18.