Part One of The Light of Egypt, The Science of the Soul, presents itself as the work of a single author, an occultist and astrologer whose themes echo those of Emma Hardinge Britten. Part Two, Science of the Stars, refers to its authors as “we” and internal evidence as well as correspondence indicates a close collaboration between Burgoyne and Grimké. She had no prior astrological training or background in occultism, while he lacked her philosophical education and training as a writer. They complemented each other’s strengths.
The 1900 two volume edition added an entire new volume while leaving the first intact as a reprint of the 1889 one volume edition. The publishers took liberties with the name, reputation, and writings of Burgoyne which were expanded in 1963 with a new edition introducing more mediumistic interpolations. While these editorial actions make most of the writings attributed to Burgoyne questionable, Sarah appears to have been represented honestly by her publishers other than lack of credit for co-authorship of The Light of Egypt.
Much of Science of the Stars parallels Grimke’s A Tour Through the Zodiac, as can be seen by comparison of the language and content of the two tomes. The concluding chapter, more metaphysical than astrological in tone, provides the strongest evidence that Grimke played a major role in creation of The Light of Egypt. This suggestion was originally found in the earliest book publications of Elbert Benjamine from the 1920s, and confirmed by Grimke family correspondence in Washington, D.C.
[this appears as the introduction to a new appendix to the slightly revised Sarah Stanley Grimke Collected Works as available in print on Amazon or online free of charge at academia at the link provided in Recommended Reading]