With Darwin's publication of The Origin of the Species in 1859, the validity of the three major Western religions was called into serious question by science. In the wake of the scientific progress, made at breakneck speed in the late-nineteenth and early-twentieth century, it seemed as if science and spirituality were increasingly becoming mutually exclusive. However, Theosophy, a hybrid science-religion founded by Madame Helena Petrovna Blavatsky in 1875, sought to reconcile science and the supernatural by using the former to explain the latter. For Blavatsky, the miraculous and the paranormal did not defy scientific explanation; they simply could not be explained through a contemporary understanding of science. Blavatsky's Theosophy was predicated on belief in a secret knowledge, known to ancient civilizations but lost to modern man that represented a deep, true understanding of nature. When realized, this insight allowed for the accomplishment of the seemingly miraculous, not by magic but by science. Theosophy's influence on canonical, highbrow modernists such as James Joyce and W.B Yeats is well known. However, its impact on the more widely read novelists of the day has been less studied and this dissertation in part fills that critical void. After an introduction to Blavatsky's Theosophy, this project moves into a discussion of Dracula. An understanding of Theosophy provides new insight into the novel's conflict between science and the supernatural. It also provides a new way to view Dr. Abraham Van Helsing., who embraces both the scientific and the unexplainable in much the same way Theosophy did. This project also includes a chapter on H. Rider Haggard's most enduring literary creation, the femme fatale Ayesha. By examining, through the lens of Theosophy, all four Haggard novels in which She appears, I offer a new interpretation of this enigmatic character. Specifically, I argue that Ayesha is a fallen Theosophical adept. The final author included in this project is Marie Corelli, one of the world's first bestselling authors. Much of her fiction seeks to reconcile spiritualist beliefs with traditional Christianity. She does so using science, and I argue that she borrows heavily from Blavatsky and Theosophy.