1. The relevance of planetary interiors

2. How does a planet differ from a rock or a cloud of gas?

3. What are planets made of?

4. “Rocks”, “ices” and “gases”

5. What are the pressures inside planets?

6. How do we figure out the behavior of materials at high pressure?

7. How can external measurements tell us about what's inside a planet?

8. The gravity field and moments of inertia

9. Observed heat flows

10. Expected heat flows

11. The conductive (or radiative) state

12. Why are planetary magnetic fields interesting?

13. What fields are observed?

14. What is the geometry of large fields?

15. Where do magnetic fields come from?

16. Why do some planets have dynamos while others do not?

17. Concluding comments