This talk would be part of the panel “Umberto Eco’s Lector in fabula/The Role of the reader 40 years later”. Lector in fabula was published in Italian in 1979 and it represents Eco’s most important contribution to narrative theory. A short version of this book was translated, in the same year, in English with the title The Role of the Reader. In these works Eco applies to narrative texts his particular kind of semiotics, focused on the concept of interpretation. From a narrative point of view, this means that the text is considered only as a starting point of a process (an interpretative process) which is conducted by the reader. Eco used to say that the text is full on “unsaid”, i.e. that only a small part of the meaning of a text is explicitly present in the text itself; the rest is brought by the reader, according to his knowledge (his encyclopedic competence) and his inferential capacities. It is no coincidence that the Italian subtitle of Lector was “The interpretative cooperation in narrative texts”. In the same years, similar themes were treated by scholars belonging to the so-called “Constance School”, whose most important members were Hans Robert Jauss and Wolfgang Iser. Jauss and Iser were among the founders of a “reception theory” that, since its name, shows many common issues with Eco’s theory. The “implied reader” introduced by Iser, for instance, has more than an analogy with the “model reader” adopted by Eco. Nevertheless, these two approaches have also important differences and Eco’s work is fully along the lines of the tradition of semiotics and seems to be more influenced by cognitive sciences. The aim of the proposed talk is to reconstruct origins, references, models and methods of both Eco’s narrative thought (as expressed mainly in Lector) and of Constance School (and above all of Jauss and Iser), in order to identity and discuss convergences and differences between two of the most important contribution to 20th century narratology.