My interest in studying subject knowledge first surfaced in the early 1970s. In Britain at this time there was a wave of change in secondary schooling from a previously selective ‘tripartite’ system towards a fully comprehensive system where all types and abilities of children were grouped under the roof of one school. This transformation in the organization of secondary schooling led to an interesting series of curriculum debates both within schools and outside schools about the form that the comprehensive school curriculum should take. In addition to comprehensive reorganization, the regime of school examinations was fairly liberal at the time and a good deal of work was done to define ‘mode 3’ examinations. These examinations were set up and partially conducted by the teachers themselves in association with examination boards (the Associated Examining Board was a pioneer in developing this mode).