The detective fiction (tantei shōsetsu) genre is one that came into Japan from the West around the time of the Meiji Restoration (1868), and soon became wildly popular. Again in recent years, detective fiction has experienced a popularity boom in Japan, and there has been an outpouring of new detective fiction books as well as various television and movie adaptations. It is not a revelation that the Japanese detective fiction genre, while rife with imitation and homage to Western works, took a dramatic turn somewhere along the line, away from celebrated models like Poe, Doyle, and Christie, and developed into a unique subgenre of Japanese prose. However, despite its popularity and innovation, Japanese detective fiction has often been categorized as popular literature (taishū bungaku), which is historically disregarded as vulgar and common. My thesis first consists of a brief introductory history oftantei shōsetsugenre in Japan. This includes a discussion of Japanese writers' anxiety concerning imitation of Western forms and their perception of themselves as imposters and imitators. Following this, I examine the ways in whichtantei shōsetsuwriters--particularly Edogawa Ranpo (1894 - 1965), the grandfather of the genre in Japan--began to deviate from the Western model in the 1920's. At the same time, I investigate the bias againsttantei shōsetsuas a vulgar or even pornographic genre. Through a discussion of literary critic Karatani Kōjin's ideas on the construction of depth in literature, I will demonstrate how Edogawa created, through his deviance from the West, a new kind of construction in detective fiction to bring a different sort of depth to what was generally considered merely a popular and shallow genre. This discussion includes a look at the ideas of Tsubouchi Shōyō on writing modern novels, and Japanese conceptions of "pure" (junsui) and "popular" (taishū) literature. Through an examination of several of Edogawa's works and his use of psychology in creating interiority in his characters, I propose that the depth configuration, put forth by Karatani in his critique of canonical modern Japanese literature, is also present in popular fiction, like Edogawa'stantei shōsetsu. When viewed through the lens of Karatani's depth paradigm, we discover how detective fiction and the vulgarity therein may actually have more in common with "pure" fiction created by those writers who followed Shōyō's prescriptions. In the final section of the introduction, I propose a definition of Japanese detective fiction that links Edogawa's works from the 1920's to the contemporary Japanese detective novel After-Dinner Mysteries (Nazotoki wa dinaa no ato de, 2010), by Higashigawa Tokuya. Thus we see that many of the themes and conventions present in Edogawa remain prevalent in contemporary writing. Finally, I present my translation of the first two chapters of After-Dinner Mysteries.