Lee Shulman, then Professor of Education and Affiliate Professor of Psychology at the School of Education, Stanford University, after lamenting George Bernard Shaw’s disparaging characterisation of teachers (“He who can, does. He who cannot, teaches”), looked at what was covered in the California State Board examination for elementary school teachers from March 1875. These were all very specific and most were content-related. Fast forward to 1985 and they were all fuzzy and relational. The big question here is: where did the subject matter go? Shulman discusses what teachers should know and do and the term Pedagogical Content Knowledge is born. He concludes: “Those who can, do. Those who understand, teach”.