1. Introduction -- 2. Product formulation -- 3. The importance of process water -- 4. Phase changes -- 5. The thermal properties of formulations -- 6. Thermal analytical methods -- 7. The freezing process -- 8. The primary drying process -- 9. Secondary drying processes -- 10. Product properties -- 11. Vacuum technology -- 12. Container-closure system -- 13. Effect of vacuum freeze-dryers : present and future.