John: To Emi Smith and Stacy Hiquet for arranging for the publication. To Jenny Davidson, for watching over the schedule and making it happen. Thanks to Marcia for the tremendous technical editing effort. You have made this book possible. To Boris for creating Visual Formula and working on a tight schedule. And to Janet for being an inspiration. Amy, thank you for working problems.
Boris: Thanks to my wife Janet and son Leonid for creative advice about how to present math and for testing Visual Formula. Also, to John and Marcia for involving me in this exciting project.