An introduction to the search for extra-terrestrial intelligence through the lens of Fermi's paradox, discussing methodology and potential solutions.

Preface; Part I. Introduction: 1. Introducing the paradox; 2. Fact A ¿ the great silence; 3. Classifying scenarios and solutions to the paradox; Part II. Rare Earth Solutions: 4. Habitable worlds are rare; 5. Life is rare; 6. Intelligence is rare; Part III. Catastrophist Solutions: 7. Doomsday arguments; 8. Death by impact; 9. Death by terrestrial disaster; 10. Death by star; 11. Death on a galactic scale?; 12. Death by unsustainable growth; 13. Death by self-induced environmental change; 14. Self-destruction at the nanoscale; 15. Artificial intelligence and the singularity; 16. War; 17. Societal collapse; Part IV. Uncommunicative Solutions: 18. Intelligent life is new; 19. Exploration is imperfect; 20. Probe exploration is dangerous; 21. The aliens are quiet; 22. They live too far away; 23. The zoo/interdict hypothesis; 24. The simulation hypothesis; 25. They are already here; 26. They were here long ago; Part V. Conclusions: 27. Solving Fermi's paradox; Appendix A. A database of solutions to Fermi's paradox; References; Index.