Argumentation theory is an interdiscipliniray field which attracts attention from e.g. philosophers, logicians, computer scientists, linguists, legal scholars and speech communication theorists. Most of the research in this field is informal. It is one of the sources of inspiration for my own work and occasionally I publish in this field. I wrote a paper for ISSA-02 on deductivism and a paper for the Argumentation journal on the relevance of Toulmin's The Uses of Argument for AI & Law, titled AI & Law, logic and argument schemes. I also published a chapter on argument schemes in the Festschrift for Douglas Walton. At ISSA-2010 I gave a talk with the best title I ever used: argumentation without arguments :-) (later published in the Argumentation Journal). In a paper for Studies in Logic I sketch my general view on the relation between formal and informal approaches to argumentation.