1. The universal mollusk -- 2. The size of space -- 3. The hall of mirrors -- 4. The four scales of geometry -- 5. Absolute or relative space? -- 6. Celestial mirages -- 7. Black hole -- 8. Foam, strings, and loops -- 9. From relativity to the big bang -- 10. What is the curvature of the universe? -- 11. Open or closed? -- 12. The knowledge of places -- 13. From the cylinder to the pretzel -- 14. Fascinating shapes -- 15. Topology and relativity -- 16. Small, strange universes -- 17. Topological mirage -- 18. Hunting for ghosts -- 19. Midnight suns -- 20. Cosmic crystallography -- 21. Circles in the sky -- 22. Inflation, the infinite, and the folds -- 23. Maya -- 24. A brief history of space -- 25. The edge paradox -- 26. The dark night paradox -- 27. Non-Euclidean geometries -- 28. Cosmos and logos -- 29. Cosmic questions -- 30. Expansion and the infinite -- 31. Galaxies in flight -- 32. The rate of expansion -- 33. The age of the universe -- 34. Astronomical distances -- 35. Cosmic mathematics -- 36. Cosmic repulsion -- 37. Dark matter -- 38. The cosmic microwave background -- 39. Is the universe flat? -- 40. Symmetry -- 41. Polyhedra -- 42. The classification of surfaces -- 43. The classification of three-dimensional spaces -- 44. Topos and cosmos -- 45. Afterword : listening to the cosmic drum.