Although argumentation plays an essential role in our lives, there is no integrated area of research on the psychology of argumentation. Instead research on argumentation is conducted in a number of separate research communities that are spread across disciplines and have only limited interaction. With a view to bridging these different strands, we first distinguish between three meanings of the word “argument”: argument as a reason, argument as a structured sequence of reasons and claims, and argument as a social exchange. All three meanings are integral to a complete understanding of human reasoning and cognition. Cognitive psychological research on argumentation has focused mostly on the first and second of these meanings, so we present perspectives on argumentation from outside of cognitive psychology, which focus on the second and third. Specifically, we give an overview of the methods, goals, and disciplinary backgrounds of research on the production, the analysis, and the evaluation of arguments. Finally, in introducing the experimental studies included in this special issue, which were conducted by researchers from a range of theoretical backgrounds, we underline the breadth of argumentation research as well as stress opportunities for mutual awareness and integration.