Case studies are widely used, particularly by researchers in education. While they are widely used, and have provided some of the most penetrating and challenging research in education and its practice, they may lack coherence and direction. A structure, is therefore, suggested for the operationalisation of case study research in teaching and in education more generally which involves consideration of the selection of case subjects, the choice of analytical focus and the varieties of form which the study itself may actually take. Using this structure, it is possible to give direction and coherence to the study while allowing its design to pursue any of a broad range of trajectories.