This doctoral thesis is about knowledge and knowing. It considers how the medium by which knowledge is stored and shared influences perceptions about the value and validity of knowledge. The analysis is based on the idea that the unique material composition of the knowledge media of the time, rather than being merely a conduit for transmitting ideational content, deeply influences beliefs about knowledge. A number of theorists (Eisenstein, 2013; McLuhan, 1962, 1969, 1994; Postman, 2005; Ong, 1977a, 2004, 2012) have analysed how the material composition of mass-print has influenced perceptions of knowledge. Walter Ong (2004) conducted an extensive analysis of early forms of textbooks. In this analysis he found that textbooks have profoundly influenced epistemological beliefs since the Enlightenment, but their influence arose not as a result of good pedagogical design, but as an unintended consequence of the unique affordances and constraints of the highly mechanised production cycles associated with mass-printed texts. As a result of the mechanical processes associated with mass-printing beliefs about knowing and knowledge were based on representations of the world laid out on the printed page (Ong, 2012). Until approximately 35 years ago the Western world used mainly the same primary media for representing, storing and disseminating pedagogical knowledge that had been used for the previous 500 years. In other words the material composition of the media by which knowledge has been transacted has been stable. But it is clear that a period of intense change is occurring as knowledge media are increasingly digitised at all stages of their production, distribution and consumption cycles. As a result of the processes of digitisation knowledge media are more multimodal, increasingly dispersed beyond one certified knowledge medium and increasingly located outside the nexus of the classroom. Media ecologists, particularly McLuhan (1994) and Ong (1977a, 2004, 2012), have speculated about the epistemological changes that the digitised knowledge environment would bring, but they tended to take a hypothetical approach to considering these changes. This research seeks to bring a more fine-grained methodological approach to these speculations by developing a media-based methodology (or lens) that shows how knowledge seekers’ incremental sensory interactions with the modal composition of knowledge media are mediating changes to beliefs about knowledge. This research compares three specific examples of knowledge media diachronically along the material axes of time, space and the extent to which the authentic voice of the ‘others’ who are mutually engaged in the knowledge transaction can be heard. The three media are: a 1960s classroom textbook—Vernon, A. (1965). Human interaction: An introduction to sociology. New York, NY: The Ronald Press Company; a classroom textbook from 2010—Carl, J. (2010). Think sociology. Upper Saddle River, NJ: Prentice Hall; and the Wikibook— Introduction to Sociology (http://en.wikibooks.org/wiki/Introduction_to_Sociology). The research finds that, as knowledge media are becoming increasingly digitised, a number of subtle epistemological changes are emerging: knowing is increasingly becoming a process of emotional connection with others rather than intellectual engagement with complex analytic categories; personal stories are becoming valued as a way of coming to know; and interpersonal connectedness and trust are increasingly perceived as valued sources of authority. In other words, the digitised knowledge environment is, rather serendipitously, increasingly facilitating more constructivist beliefs about knowledge. Despite this increased capacity for digitised knowledge media to mediate more constructivist personal epistemological beliefs, this research finds, rather alarmingly, that there are parallels between Ong’s (2004) findings and the current epistemological period: new knowledge media are being incorporated into classroom practice with limited attention to the influence that their modal composition is having on beliefs about knowledge and knowing. This inattention has significant implications for learning and teaching at this time of large-scale investment in new knowledge media. The research provides insight into how the characteristics of the ‘packaging’ of knowledge shapes perceptions of it. It provides a lens to help teachers, educational policy makers and planners avoid sleepwalking into the 21st century with 19th century perceptions (McLuhan, Fiore & Agel, 1967), and to advance academic consideration of these matters.