Lee concludes his explanation of Kepler's Laws of Planetary Motion by proving, with mathematical rigour as always, Kepler's Third Law - the square of the period of a planet moving around its elliptical orbit is proportional to the cube of the semi-major axis of that orbit.

1. The Fundamental Theorem of Calculus
2. The Fundamental Theorem of Calculus II
3. Leibniz's Quest for Pi
4. Leibniz's Quest for Pi II
5. Leibniz's Quest for Pi III
6. Wallis' Product I: Integrating sin Raised to the nth Power
7. Wallis' Product II: Using the Reduction Formula
8. Wallis' Product III: Taking the Limit
9. Wallis' Product IV: Taking the Limit
10. In Search for the Orbit
11. Kepler's Laws: Preliminaries I
12. Kepler's Laws: Preliminaries II
13. Kepler's First Law I
14. Kepler's First Law II
15. Kepler's Second Law
16. Kepler's Third Law
17. Hyperbolic Functions: Definitions and Graph of cosh(x)
18. Hyperbolic Functions: Graph of sinh(x)
19. Hyperbolic Functions: Derivatives
20. The Catenary Problem