THE REAL WORLD OF MATHEMATICS, SCIENCE, AND TECHNOLOGY EDUCATION In this Preface, I would like to focus on what I mean by "education" and speak about the models and metaphors that are used when people talk, write, and act in the domain of education. We need to look at the assu- tions and processes that the models and metaphors implicitly and explicitly contain. I feel we should explore whether there is a specific thrust to mat- matics education in the here and now, and be very practical about it. For me education is the enhancement of knowledge and understanding, and there is a strong and unbreakable link between the two. There seems l- tle point in acquiring knowledge without understanding its meaning. Nor is it enough to gain a deep understanding of problems without gaining the appropriate knowledge to work for their solution. Thus knowledge and understanding are each necessary conditions for the process of education, but only when they are linked will the process bear fruit. Only in the b- anced interplay of knowledge and understanding can we expect to achieve genuine education.