Mysterious Psychic Forces by Camille Flammarion explores reports of unusual mental and psychic phenomena, including telepathy, clairvoyance, mediumship, apparitions, and other experiences associated with the study of the unexplained. Flammarion, a prominent French astronomer and scientific writer, approaches these subjects through observation, testimony, and discussion of reported phenomena.

The work reflects the late nineteenth- and early twentieth-century interest in investigating questions at the boundary between science, psychology, and spiritualism. Flammarion examines accounts of extraordinary experiences while considering possible explanations and the difficulties involved in evaluating such claims.

As a historical work on psychic research and spiritualism, Mysterious Psychic Forces provides insight into the period's fascination with unexplained phenomena and the attempts of contemporary thinkers to understand the relationship between consciousness, perception, and the unknown.