This special issue is to celebrate the twenty-fifth’s anniversary of a highlight of modern argumentation theory: Speech Acts in Argumentative Discussions. A Theoretical Model of the Analysis of Discussions Directed towards Solving Conflicts of Opinion by Frans H. van Eemeren and Rob Grootendorst.1 Speech Acts is a groundbreaking book that can be seen as the kick-off of the development of the pragma-dialectical approach to argumentation.2 It marks the beginning of this development but it is also surprisingly complete. It is remarkable that all major elements of the pragma-dialectical theory of argumentation can already be found here; sometimes in an embryonic state, but mostly in a more elaborated and worked-out formThis special issue is to celebrate the twenty-fifth’s anniversary of a highlight of modern argumentation theory: Speech Acts in Argumentative Discussions. A Theoretical Model of the Analysis of Discussions Directed towards Solving Conflicts of Opinion by Frans H. van Eemeren and Rob Grootendorst.1 Speech Acts is a groundbreaking book that can be seen as the kick-off of the development of the pragma-dialectical approach to argumentation.2 It marks the beginning of this development but it is also surprisingly complete. It is remarkable that all major elements of the pragma-dialectical theory of argumentation can already be found here; sometimes in an embryonic state, but mostly in a more elaborated and worked-out form