Introduction. A brain-based approach to dreaming -- 1. The study of dreaming in the nineteenth century -- 2. Psychoanalysis and dreaming -- 3. Dream investigation in the early twentieth century -- 4. A spark of nature's fire : the electrical brain -- 5. The regulation of consciousness by the brain stem -- 6. The discovery of REM sleep and dreaming -- 7. A window on the brain : neural activity -- 8. A war of nerves : the reciprocal-interaction model of REM-sleep generation -- 9. The brain as a dream machine : an activation-synthesis hypothesis of dreaming -- 10. The form of dreams -- 11. The form of dream sensation -- 12. The form of dream movement -- 13. The bizarreness of dreams -- 14. The interpretation of dream form -- 15. The functions of REM sleep and dreaming.