The Diploma Programme was the first programme to be devised and implemented by the International Baccalaureate over fifty years ago. Since its creation, the curriculum upon which the programme is based has been continuously developed to take into account the rapidly changing needs of students, schools, higher education and employment contexts. For much of that time, the programme has included three essential components that must be undertaken by students who wish to graduate with the Diploma: Theory of Knowledge, Extended Essay and Creativity, Activity, Service (CAS). Taken together, over time these have come to be regarded as a core of the Diploma Programme, although they were not described as such at the outset. This edited collection is intended to provide input into the current review of the IB Diploma Programme. It comprises contributions from experienced authors - researchers and practitioners - who were invited to reflect upon the nature of the core as it exists at present, to raise issues in relation to the future development of the core, and to share experience in the learning and teaching of the core components across a wide range of schools, in both national and international systems of education. Questions concerning the concept of the core as a whole, developing students as internationally-minded thinkers, and the challenges of bringing coherence to the core in establishing a holistic approach to the curriculum, underpin the individual chapters throughout. Contributors: Edward Allanson, Tom Brodie, John Cannings, Christian Chiarenza, Mary Donnellan, Jenny Gillett, Robin Julian, Julian Kitching, Justin Laleh, Ann Lautrette, James MacDonald, Shona McIntosh, Heather Michael, Paul Regan, John Royce, John Sprague, George Walker.