Provides an overview of research into design of argumentation software, focusing on defeasible argumentation as it occurs in the law. - Съдържа: Introduction -- The first prototype : Argue! -- Improved naturalness : ArguMed 2.0 -- A logical extension : ArguMed 3.0 based on DefLog -- A comparison of argument assistants and mediators -- Theories of defeasible argumentation -- Argument assistants : conclusions and prospects.*