December’s Book of the Month is *The Legacy of Felix Klein* by Hans-Georg Weigand, William McCallum, Marta Menghini, Michael Neubrand and Gert Schubring (Eds.) (2018).

Throughout his professional life, Felix Klein emphasised the importance of reflecting upon mathematics teaching and learning from both a mathematical and a psychological or educational point of view, and he strongly promoted the modernisation of mathematics in the classroom. Felix Klein developed ideas on university lectures for student teachers, which he later consolidated at the beginning of the last century in the three books Elementary Mathematics from a higher standpoint. At the 13th International Congress on Mathematical Education (ICME-13) 2016 in Hamburg, the “Thematic Afternoon” with the The Legacy of Felix Klein as one major theme, provided an overview of Felix Klein’s ideas. It highlighted some developments in university teaching and school mathematics related to Felix Klein’s thoughts stemming from the last century. Moreover, it discussed the meaning, the importance and the legacy of Klein’s ideas nowadays and in the future in an international, global context.

The whole book intends to show that many ideas of Felix Klein can be reinterpreted in the context of the current situation, and give some hints and advice for dealing today with current problems in teacher education and teaching mathematics in secondary schools. In this spirit, old ideas stay young, but it needs competent, committed and assertive people to bring these ideas to life.

(–> Link to Springer)