1. Motivation for the sequential approach and selected applications -- 2. Background on probability and statistics -- 3. Sequential hypothesis testing : two simple hypotheses -- 4. Sequential hypothesis testing : multiple simple hypotheses -- 5. Sequential hypothesis testing : composite hypotheses -- 6. Statistical models with changes : problem formulations and optimality criteria -- 7. Sequential changepoint detection : Bayesian approach -- 8. Sequential change detection : non-Bayesian approaches -- 9. Multichart changepoint detection procedures for composite hypotheses and multipopulation models -- 10. Sequential change detection and isolation -- 11. Selected applications.