Despite its enormous popularity and recognition as one of the representative American literary works of the turn of the last century, Paul Auster`s The New York Trilogy has been largely seen as a product of the Postmodern temper. The three novellas that comprise the Trilogy deal with the familiar themes and plot schemes of popular detective novels, yet early reviewers have been exasperated by the ambiguities surrounding the narrative center, the deliberate employment of multiple narrative schemes, satisfactory sense of closure, and mix match of intertexual undercurrents. Consequently, scholars in the past have assumed that a `subversive` agenda was latent in the Trilogy, a backhanded counter-discourse of the detective story genre, which one critic refers to as "anti-detective fiction." This paper, however, seeks to show that the elements of the works in the Trilogy can be analyzed well within the traditional, and well established, detective story discourse. Through close reading of the text, the paper attempts to illustrate that the author deliberately engages his readers in what is known within the mystery and detective story genre as "the ratiocination effect," namely the inclination for analytic deduction based on clear and/or inconspicuous clues provided within the story. The paper focuses on the quandaries surrounding the issue of authorship of the three sections of the Trilogy, arguing that it is here that Auster most solicits the ratiocinative participation of his readers.