Language: Brazilian Portuguese. The questions that Umberto Eco raises in this work are, in appearance, very simple, but, in reality, fundamental for a theory of reading a fictional text. Indeed, the basic questions underlying your analysis are: Who is effectively the reader of a fable? What is your role? How and to what extent does your interpretation enter into this decoding? But, to answer such questions, the reader of Lector in Fabula resorts to all the elements provided by modern semiotic research and, above all, to the proposal of the act of reading that Roland Barthes embodied in the expression 'pleasure of the text'. For, in fact, for Eco, no less than for the French critic, it is a matter of declaring not only 'what' a text provides, but also 'why' what it provides is indissolubly linked to the fruition of the actualized object. In the systematic and persistent pursuit of these targets, 'Lector in Fabula' could not remain merely on the abstract plane. And, undoubtedly, masterful is the application that Umberto Eco makes of the notions and structures that he raises in the theoretical discourse, turning his focus to the microanalysis of a concrete example.. Of course, Alphonse Allais' account fits perfectly, in its composition and style, to the purpose of the analyst; but what results from this critical incision is a remarkable clarification, transparent not only to the scholar of these matters, of how the textual machine is organized and functions, what game occurs between 'the said' and 'the unsaid', what is drawn in the interstices and in the blank spaces, and what possible developments are made, in the form of 'phantom chapters', by the receiver-reader, that is, by virtue of which strategies and what reading encyclopedias a text adequately performs its role, realizing itself as a fictional universe.