Table of Contents:

1. To my reader.
2. On our inability to do much.
3. On the reliability of mechanisms.
4. On our mental aids.
5. An example of a correctness proof.
6. On the validity of proofs versus the validity of implementations
7. On understanding programs
8. On comparing programs
9. A first example of step-wise program composition.
10. On program families.
11. On trading storage space for computation speed.
12. On a program model.
13. A second example of step-wise program composition.
14. On what we have achieved.
15. On grouping and sequencing.