The mu‘amma was one of the most popular literary genres in the Persianate literature of the late medieval and early modern periods. By its simplest definition, the mu‘amma is the practice of codifying a person’s name in a poem. The name is encoded in the visual structure of the poem, and the reader of the poem is expected to discover how the name is encoded in the poem. Given that deciphering a mu‘amma involves a process of puzzle-solving, the genre is usually classified under the general rubric of riddles. However, the mu‘amma diverges from riddle as traditionally understood in several ways. First, the answer to the mu‘amma is known to the decoder at the beginning. In other words, the name which is encoded in the poem is already known to the decoder; the point is rather to discover the mechanics of its encoding. Second, riddles may refer to anything, animate or inanimate, but a mu‘amma must encode a person’s name. In contemporary and near contemporary sources, the famous Timurid historian Sharaf al-Din ‘Ali Yazdi (d. 1454) is usually credited with inventing the mu‘amma genre in his Hulal-i Mutarraz. Yazdi was also a prominent member of a lettrist intellectual circle in Iran and Central Asia. Yazdi and his peers in Iran were dedicated to using the science of letters as a method of understanding the cosmic order. In my presentation, I will explore the connections between the mu‘amma genre and certain techniques employed by the philosophical science of letters in the 15th century. I will argue that the mu‘amma was not simply a poetical genre, but that it was in fact a form of divinatory practice, which Timurid intellectuals of western Iran used in order to riddle the secrets of the cosmic order. Their method was ultimately radical and subversive to a certain extent, because they believed that such an approach would enable them to understand what the cosmic order was and how it was constructed by the divine creative power. That their activities were suppressed and the mu‘amma genre was reduced to a simple game of riddle solving in the early 16th century is one of the tragic episodes of late medieval intellectual history.