Goffman’s now seminal work (1959) remains significant in highlighting, inter alia, the ways in which the tools people appropriate to perform their different roles are much more than merely adjuncts to the person. Central to Goffman’s (1959: 34) theory regarding the process of identity production are ‘items of expressive equipment’, which he defines as ‘the items that we most intimately identify with the performer himself ’. In my own Father’s case, to which I refer in the opening reflection of this chapter, these items were the tools which enabled him to carry out his work and in which he took great pride because of the precision and skill with which they allowed him to fashion other tools as part of a much larger process of aero-engine design and manufacture. Thus, throughout this chapter I explore the various knowledge bases that point to the different factors affecting teachers’ appropriation of technological tools as they seek to construct the pedagogical tools for their professional work as part of a larger system that is dynamic and subject to change. The process of appropriation I define as the different ways in which teachers make cultural or technological tools their own, bringing their own understanding and purpose to tools. I begin by establishing the need for a view of professional learning with technologies that foregrounds the importance of teachers as active agents within a dynamic conceptualisation of technology and education (Somekh, 2007; Pachler, Cook and Bachmair, 2010). The second half of the chapter examines the process of professional learning in more depth, incorporating technologies, as a complex ecological system of mediated activity but within which teachers are always positioned centrally, as pedagogical toolmakers.