First, to all the teachers who have used Discovering Geometry, a sincere thank youfor your wonderful support and encouragement. I wish to thank my alwaysdelightful and ever-so-patient students for their insight, humor, and hard work.I also wish to thank the many students across the country who have written to mewith their kind words, comments, and suggestions. And thanks to the marketingand sales staff at Key Curriculum Press for their successful efforts in bringing thefirst three editions into so many classrooms.