1. Difficulties Associated with the Classification of the Diabetic Syndrome -- 2. Overview of the Etiopathogenesis of Type 1 Diabetes -- 3. Preventing Type 1 Diabetes in Animal Models -- 4. Prevention Projects for Human Type 1 Diabetes -- 5. Overview of the Etiopathogenesis of Type 2 Diabetes Mellitus -- 6. Possibilities for Preventing Type 2 Diabetes Mellitus -- 7. General Evaluation of the Prophylaxis of Diabetes Mellitus -- 8. Insufficiently Utilized Opportunities