Temporada 4
Imagens
| # | Imagem | Título | Exibido |
|---|---|---|---|
| 1 |  | Hitler's Secret Weapon | 5 de jan. de 1977 |
| 2 | The Hot-Blooded Dinosaurs | 12 de jan. de 1977 | |
| 3 | What Price Coal? | 19 de jan. de 1977 | |
| 4 | The Sunspot Mystery | 2 de fev. de 1977 | |
| 5 | The Plastic Prison | 9 de fev. de 1977 | |
| 6 | Incident at Brown's Ferry | 23 de fev. de 1977 | |
| 7 | Bye Bye Blackbird | 2 de mar. de 1977 | |
| 8 | The Pill for the People | 9 de mar. de 1977 | |
| 9 | The Gene Engineers | 16 de mar. de 1977 | |
| 10 | Sociobiology : The Human Animal | 23 de mar. de 1977 | |
| 11 | The Wolf Equation | 30 de mar. de 1977 | |
| 12 | The Dawn of the Solar Age | 20 de abr. de 1977 | |
| 13 | The Business of Extinction | 20 de abr. de 1977 | |
| 14 | The Red Planet | 27 de abr. de 1977 | |
| 15 | The Tongues of Men : Disaster at Babel (1) | 11 de mai. de 1977 | |
| 16 | The Tongues of Men : A World Language? (2) | 18 de mai. de 1977 | |
| 17 | Linus Pauling: Crusading Scientist | 1 de jun. de 1977 | |
| 18 | Across the Silent Barrier | 22 de jun. de 1977 | |
| 19 | The New Healers | 29 de jun. de 1977 |