This paper argues that Umberto Eco had a sophisticated theory of abductive reasoning and that this theory is fundamentally akin to Peirce\u2019s both in the analysis and in the justification of this kind of reasoning. The first section expounds the essentials of Peirce\u2019s theory of abduction, and explains how Peirce moved from seeing abduction as a kind of reasoning to seeing it as a stage of the larger process of inquiry. The second section deals with one of Eco\u2019s paradigmatic examples of abduction, i.e., William of Baskerville\u2019s abduction concerning the horse Brunellus in the overture of The Name of the Rose, and shows that, just like in Peirce\u2019s three-stages model of inquiry, William\u2019s abductions are verified by m...