This translation of two of Dr. Steiner's works on Haeckel was originally published by the Theosophical Society in one volume with an essay on the Working of Karma. By the courtesy of the Theosophical Society and with the kind consent of the translator, Dr. Bertram Keightley, LL.D., M.A., the parts referring to Haeckel are now reprinted in this volume.
In the original German the two parts were published separately:
- Haeckel und seine Gegner (Haeckel and his opponents): a brochure, 1900, page 1.
- Haeckel, die Welträtsel und die Theosophie (Haeckel, “the Riddle of the Universe” and Theosophy): a lecture given at Berlin, 5th October, 1905.