Unlike the classical sources, nineteenth-century historians of religion characterized certain Hellenistic initiatory cults as "Mystery Religions." This was also the century in which the literary genre of mysteries (i.e., detective stories) developed (e.g., E. A. Poe). Was the nineteenth-century development of literary mysteries and the contemporaneous characterization of some Hellenistic initiatory practices by historians of religion also as "mysteries," especially, those characterized by R. Reitzenstein as "reading mysteries" (Lesemysterien), coincidental? I suggest that mystery novels may be read for insights into the historical and/or cultural landscape of Romanticism. These novels disclose a fascination with "mysteries," a "presentist" bias that influenced nineteenth-century characterizations of Hellenistic initiatory cults by historians of religion. In addition to a shared cultural influence, common neurocognitive features underlie both the act of reading itself, especially reading detective novels, and the Lesemysterium hypothesis.