Gabriele Kaiser is a Professor of Mathematics Education at the University of Hamburg. She holds a master's degree as a teacher for mathematics and humanities and completed her doctorate in mathematics education on applications and modelling. She is Editor-in-Chief of "ZDM -- The International Journal on Mathematics Education (formerly Zentralblatt fuer Didaktik der Mathematik) and since July 2007 she serves as president of the "International Community of Teachers of Modelling and Applications" (ICTMA), an ICMI affiliated Study Group. Werner Blum is a Professor of Mathematics Education at the University of Kassel. He got a Ph.D. in Pure Mathematics in 1970 from the University of Karlsruhe. His main research areas include empirical studies into the teaching and learning of mathematics and the professional knowledge of mathematics teachers, national and international comparative studies (especially PISA), quality development in mathematics teaching as well as applications and modelling in mathematics education. Rita Borromeo Ferri is a Guest Professor of Mathematics Education at the University of Hamburg. She holds a master's degree as a teacher for mathematics and geography and completed her doctorate in mathematics education on mathematical thinking styles and her post-doc study on applications and modelling. She taught several years in school and got a teaching award of the Faculty of Education at University of Hamburg.