Carl Ludwig Siegel was born on December 31, 1896 in Berlin. He studied mathematics and astronomy in Berlin and Göttingen and held chairs at the Universities of Frankfurt and Göttingen before moving to the Institute for Advanced Study in Princeton in 1940. He returned to Göttingen in 1951 and died there in 1981.Siegel was one of the leading mathematicians of the twentieth century, whose work, noted for its depth as well as breadth, ranged over many different fields such as number theory from the analytic, algebraic and geometrical points of view, automorphic functions of several complex variables, symplectic geometry, celestial mechanics.

One. The Three-Body Problem.-
1. Covariance of Lagrangian Derivatives.-
2. Canonical Transformation.-
3. The Hamilton-Jacobi Equation.-
4. The Cauchy Existence Theorem.-
5. The n-Body Problem.-
6. Collision.-
7. The Regularizing Transformation.-
8. Application to the Three-Body Problem.-
9. An Estimate of the Perimeter.-
10. An Estimate of the Velocity.-
11. Sundman's Theorem.-
12. Triple Collision.-
13. Triple-Collision Orbits.- Two. Periodic Solutions.-
14. The Solutions of Lagrange.-
15. Eigenvalues.-
16. An Existence Theorem.-
17. The Convergence Proof,.-
18. An Application to the Solutions of Lagrange.-
19. Hill's Problem.-
20. A Generalization of Hill's Problem.-
21. The Continuation Method.-
22. The Fixed-Point Method.. -.-
23. Area-Preserving Analytic Transformations.-
24. The Birkhoff Fixed-Point Theorem.- Three. Stability.-
25. The Function-Theoretic Center Problem.-
26. The Convergence Proof.-
27. The Poincaré Center Problem.-
28. The Theorem of Liapunov.-
29. The Theorem of Dirichlet.-
30. The Normal Form for Hamiltonian Systems.-
31. Area-Preserving Transformations.-
32. Existence of Invariant Curves.-
33. Proof of the Lemma.-
34. Application to the Stability Problem.-
35. Stability of Equilibrium Solutions.-
36. Quasi-Periodic Motion and Systems of Several Degrees of Freedom.-
37. The Recurrence Theorem.