AboutThisBook This book was ?rst suggested to Springer in 2004, though its origins go back to changes made two years earlier to the structure of the University of Hull’s Computer Science programme. At the same time, my own visualization - search was leading towards a systematic view of data and techniques that I felt could be educationally valuable. In 2003 I thus sat down with some trepidation to write a visualization course founded on research in the area but nonetheless accessible to students. This course could, however, involve no mathematics beyond GCSE, in line with university admissions practices of that time. Writing the course involved generating many new illustrations, in the form of both line drawings and visualization screenshots and, wi- ing to get maximum mileage out of this e?ort, the idea of writing a book to accompany the course came about. At the University of Hull, our practical visualization teaching is based on IRIS Explorer, an application builder-type package from NAG Ltd. Ori- nally this book was to have been both an introduction to visualization and a handbook for beginners in IRIS Explorer, with ‘virtual laboratories’ running throughout it to illustrate certain points. Following comments from revi- ers, however, its emphasis has changed.