Introduction. The Didactics of Mathematics: Approaches and Issues. A Hommage to Michèle Artigue. Bernard R. Hodgson, Alain Kuzniak, J.B. Lagrange -- Chapter 1: Didactique goes travelling: Its actual and potential articulations with other traditions of research on the learning and teaching of mathematics. Abraham Arcavi, Paolo Boero, Jeremy Kilpatrick, Luis Radford, Tommy Dreyfus, Kenneth, Ruth…