GA 326
| No. | Lecture Title | Book Title | Date | City |
|---|---|---|---|---|
| 1. | Lecture I | Origins of Natural Science | 24 Dec 1922 | Dornach |
| 2. | Lecture II | Origins of Natural Science | 25 Dec 1922 | Dornach |
| 3. | Lecture III | Origins of Natural Science | 26 Dec 1922 | Dornach |
| 4. | Lecture IV | Origins of Natural Science | 27 Dec 1922 | Dornach |
| 5. | Lecture V | Origins of Natural Science | 28 Dec 1922 | Dornach |
| 6. | Lecture VI | Origins of Natural Science | 01 Jan 1923 | Dornach |
| 7. | Lecture VII | Origins of Natural Science | 02 Jan 1923 | Dornach |
| 8. | Lecture VIII | Origins of Natural Science | 03 Jan 1923 | Dornach |
| 9. | Lecture IX | Origins of Natural Science | 06 Jan 1923 | Dornach |