Part I: The mathematical system and the general model -- 1. The basic model -- 2. Stimulus sampling and conditioning -- 3. Sequences of events -- 4. Distributions of response probabilities -- 5. The equal alpha condition -- 6. Approximate methods -- 7. Operators with limits zero and unity -- 8. Commuting operators -- Part II: Applications -- 9. Identification and estimation -- 10. Free-recall verbal learning -- 11. Avoidance training -- 12. An experiment on imitation -- 13. Symmetric choice problems -- 14. Runway experiments -- 15. Evaluations.