Charles Grant Blairfindie Allen (February 24, 1848 - October 25, 1899) was a science writer, author and novelist, and a successful upholder of the theory of evolution. In his career, Allen wrote two novels under female pseudonyms. One of these was the short novel The Type-writer Girl, which he wrote under the name Olive Pratt Rayner. Another work, The Evolution of the Idea of God, propounding a theory of religion on heterodox lines, has the disadvantage of endeavoring to explain everything by one theory. This "ghost theory" was often seen as a derivative of Herbert Spencer's theory. However, it was well known and brief references to it can be found in a review by Marcel Mauss, Durkheim's nephew, in the articles of William James and in the works of Sigmund Freud. He was also a pioneer in science fiction, with the 1895 novel The British Barbarians. This book, published about the same time as H. G. Wells's The Time Machine, which includes a mention of Allen, also described time travel, although the plot is quite different. His short story The Thames Valley Catastrophe (published 1901 in The Strand Magazine) describes the destruction of London by a sudden and massive volcanic eruption. Many histories of detective fiction also mention Allen as an innovator. His gentleman rogue, the illustrious Colonel Clay, is seen as a forerunner to later characters. In fact, Allen's character bears strong resemblance to Maurice Leblanc's French works about Arsène Lupin, published many years later; and both Miss Cayley's Adventures and Hilda Wade feature early female detectives.