This thesis presents a detailed account of what printworkers know, the way in which they know it, and what they do with that knowledge in order for production to happen : the substantive and cognitive content of print knowledge, its distribution and mobilisation. It looks at everyday industrial practice in terms more usually reserved for the knowledge of scientists, engineers or other professionals, and finds that they are also useful for characterising the substantive and cognitive content of knowledge used in a largely "blue-collar" manufacturing environment. Drawing on work from the sociology of scientific knowledge, the history and sociology of science and technology, and other relevant fields, the thesis reviews existing frameworks for conceptualising and analysing knowledge and practice, and the power relations inherent therein. It discusses the applicability (and limitations) of these frameworks to current everyday manufacturing production activity in the light of the empirical data, in order to increase understanding of technological knowledge and practice. Fieldwork was carried out in three firms in different sectors of the industry, using a variety of data collection methods including interviews, participant observation and action research/consultancy. Data are presented ethnographically, in the form of case studies. The thesis argues that social, economic, technical and political factors both structural and local shape the content and distribution of print knowledge and power within and between firms, creating both the industry's established technological communities and its day-to-day technological networks. It suggests that there are two main types of mobilisation process in print production, recursively related through institutionalisation : DEFINITION, when "common knowledge" is mobilised by individuals who belong to a technological community; and PROBLEM-SOLUTION, which requires the "collective mobilisation" of diverse personal knowledge (underpinned by common knowledge) by technological networks of heterogeneous composition. The non-human world, in the form of texts, tools and machines, is crucial to both processes and to the relation between them.