"Noss and Hoyles take on the field of Mathematics Education as a whole to develop a coherent theoretical framework that will encompass its psychological, social, pedagogical and epistemological dimensions. Their pages abound with socratic flies to torment anyone who claims to understand concepts like abstract, concrete, formal, common-sensical and even mathematics, without the context of an elaborated theory. At the same time they present the most elaborated theoretical discussion to date of how the computer presence might contribute to the development of the field." Seymour Papert, Massachusetts Institute of Technology 'I would say that the book is very readable, and contains a number of interesting details as well as the construction of a theory. It is one important step in developing a theoretical framework for the use of technology in mathematics education.' Nordic Studies in Mathematical Education, 3 (1997)