"This book is the story of a mathematics education innovation which has been very successful and continues to be improved....all teachers who are interested in improving education in any subject area and at any level would be interested in this story."—School Science and Mathematics"...presents an in-depth, detailed discussion of the Geometric Supposer and related issues in one volume. This book compares quite favorably with others of this type because it describes comparative studies of the Supposer, thereby furnishing an empirical base for its claim. Because of its depth, this book is an excellent resource for the specialist working in geometry reform or integrating technology into instruction."—The Mathematics Teacher