The general purpose of this thesis is to understand how participation in the activity of education relates to communication and tools. This purpose unfolds by drawing on possible conceivable consequences. In the fulfilment of this purpose communication, education, participation, and tools are analytically linked by a common denominator: human action. The commentary text expounds on these links, while the four included papers illustrate how these links operate in educational settings. The general purpose serves to frame a narrower purpose: a discussion of participation through computer-mediated communication in online settings of Swedish higher education. The theoretical departure derives from a transactional approach that embraces human action as an inseparable aspect of a dynamic whole, here defined as the activity of education. This activity is discussed in terms of its cultural, ecological, historical, and social aspects. This theoretical departure embraces ideas largely taken from ecological, pragmatic and sociocultural perspectives of human action. The papers include analyses of, variously, empirical material taken from interviews with students, online exchanges of utterances, syllabuses, and study-guides. Two of the papers are literature reviews. The findings indicate that participation in education is a complex boundless phenomenon that is best understood as a dynamic whole. In this whole, participation in education is culturally, ecologically, historically, and socially transformed by actions, agents, communication, tools, and the setting. In this thesis, concepts such as computermediated communication, communicative genres, dialogical intersections, and educational settings are utilised to reach a dynamic understanding. The dynamics of these findings, therefore, are a challenge to all dualistic conceptualisations of education, such as those building on the idea of learners operating in learning environments. Particularly, these findings challenge operationalisations of education that rely on computer-mediated communication and which build on the idea of so-called online learning environments. A more coherent understanding of participation in education is possible if educational research and design builds on a non-dualistic conceptualisation that includes the idea of participation being performed in a boundless activity.