The Fourth Dimension: Sacred Geometry, Alchemy, and Mathematics CW 324a by Rudolf Steiner. Listener's notes on lectures on higher dimensional space and of questions and answers on mathematical topcs. A six lecture series held in Berlin from March 24 to June 7, 1905. Two single lectures given in Berlin on November 7, 1905 and October 22, 1908. Questions and Answers from 1904 to 1922. Translated by Catherine Creeger.

1. Lecture 1: Mathematical Thinking and Reality (Berlin, March 24, 1905)

2. Lecture 2: Thoughts on four dimensional Space [Hinton's Work] (Berlin, March 31, 1905)

4. Lecture 4: Representing figures of higher dimensions in lower dimensions (Berlin, May 24, 1905)

5. Lecture 5: Relationships of cube to tesseract (Berlin, May 31, 1905)

6. Lecture 6: Further reflections on dimensions (Berlin, June 7, 1905)

7. Lecture 7: Four Dimensional Space (Berlin, November 7, 1905)

8. Lecture 8: On Higher Dimensional Space (Berlin, October 22, 1908)

9. Lecture 9: Fourth Dimension Questions and Answers 1

10. Lecture 10: Fourth Dimension Questions and Answers 2

11. Lecture 11: Fourth Dimension Questions and Answers 3