Abstract
The notions of types of dialogue and dialectical relevance are central themes in Walton’s work and the grounds for a dialectical approach to many fallacies. After outlining the dialogue models constituting the background of Walton’s account, this article presents the concepts of dialectical relevance and dialogue shifts in their application to biased argumentation, fallacious moves, and illicit argumentative strategies. Showing the different dialectical proposals Walton advanced in several studies on argumentation as a development of a dialogical system, it has proved possible to highlight the fundamental aspects of his theory in a comprehensive model of communication and interaction