A great deal of this success was due to Poe's weird and wonderful stories; still more, perhaps, to his trenchant critiques and his startling theories anent cryptology. As regards the tales now issued in 'Graham's', attention may especially be drawn to the world-famed "Murders in the Rue Morgue," the first of a series--'"une espèce de trilogie,"' as Baudelaire styles them--illustrative of an analytic phase of Poe's peculiar mind. This 'trilogie' of tales, of which the later two were "The Purloined Letter" and "The Mystery of Marie Roget," was avowedly written to prove the capability of solving the puzzling riddles of life by identifying another person's mind by our own. By trying to follow the processes by which a person would reason out a certain thing, Poe propounded the theory that another person might ultimately arrive, as it were, at that person's conclusions, indeed, penetrate the innermost arcanum of his brain and read his most secret thoughts. Whilst the public was still pondering over the startling proposition, and enjoying perusal of its apparent proofs, Poe still further increased his popularity and drew attention to his works by putting forward the attractive but less dangerous theorem that "human ingenuity could not construct a cipher which human ingenuity could not solve." This cryptographic assertion was made in connection with what the public deemed a challenge, and Poe was inundated with ciphers more or less abstruse, demanding solution. In the correspondence which ensued in 'Graham's Magazine' and other publications, Poe was universally acknowledged to have proved his case, so far as his own personal ability to unriddle such mysteries was concerned. Although he had never offered to undertake such a task, he triumphantly solved every cryptogram sent to him, with one exception, and that exception he proved conclusively was only an imposture, for which no solution was possible. The outcome of this exhaustive and unprofitable labor was the fascinating story of "The Gold Bug," a story in which the discovery of hidden treasure is brought about by the unriddling of an intricate cipher.