From the Book - Dover ed.
1. The functions of Schläfli and Lobatschefsky
2. Integral Cayley numbers
3. Wythoff's construction for uniform polytopes
4. The classification of Zonohedra by means of projective diagrams
5. Regular skew polyhedra in three and four dimensions, and their topological analogues
6. Self-dual configurations and regular graphs
7. Twelve points in PG(5, 3) with 95040 self-transformations
8. Arrangements of equal spheres in non-Euclidean spaces
9. An upper bound for the number of equal nonoverlapping spheres that can touch another of the same size
10. Regular honeycombs in hyperbolic space
11. Reflected light signals
