This paper surveys the contributions to the study of argumentation in the two decades since the work of Toulmin and Perelman. Developments include Radical Argumentativism (Anscombre and Ducot), Communication and Rhetoric (American Speech Communication Theory), Informal Logic (Johnson and Blair), Formal Analyses of Fallacies (Woods and Walton), Formal Dialectics (Barth and Krabbe), and Pragma-Dialectics (van Eemeren and Grootendorst). From the survey it is concluded that argumentation theory has been considerably enriched. If the contributions can be made to converge, a sound basis will be created for developing educational methods for producing, interpreting and evaluating argumentative discourse. Thus, argumentation theory may be instrumen...