Legacy of a Great Thinker Editorial for the Commemorative Issue for Ernst von Glasersfeld.

Context • On 12 November 2010, Ernst von Glasersfeld passed away. He was one of the most important, if not the most important, proponents of constructivist philosophy. Problem • In his life Ernst influenced many other scientists and philosophers. By whom was he himself influenced; who shaped his intellectual development? By collecting contributions from those who knew him closely or have an excellent understanding of radical constructvism we aim at presenting a cartography of the past and current state of affairs of radical constructivism. These contributions should also shed light on the question of the legacy that Ernst leaves behind. Method • Some 25 authors accepted our invitation to contribute to this commemorative issue. Some texts are reminiscence essays expressing their friendship with Ernst, others are academic papers that investigate Ernst's influence in various disciplines. Two contributions Ernst von Glasersfeld authored himself. Results • Ernst von Glasersfeld is described as an intellectual mentor for many of his students. His legacy is alive in many disciplines ranging from education science to linguistics. Implications • Ernst's impact on mathematics education is described in some detail in these articles. However, his impact on science education has also been extensive. Constructivism is a foundation stone in the thinking behind the curriculum in many countries and this collection of papers should be useful to practitioners and researchers in education. We think that the work on conceptual analysis could be used more fully as a tool for modelling emerging concepts and hope that the articles here will facilitate interest in this aspect of Ernst's work. [ABSTRACT FROM AUTHOR]