Part I. Theoretical Framework: 1. Abilities as forms of developing expertise; Part II. The Nature of Dynamic Testing: 2. An introduction to dynamic testing; 3. A capsule history of dynamic testing; Part III. Leading Modern Approaches to Dynamic Testing: 4. The approach of Feuerstein; 5. The approach of Budoff; 6. Diverse approaches to dynamic testing; 7. A three-prong approach to dynamic testing; Part IV. Two Case Studies using Dynamic Testing: 8. Using dynamic testing to reveal hidden potential; 9. Combining instruction with assessment: measuring foreign-language learning ability; 10. Measurement aspects of dynamic testing: quantifying change; Epilogue.