I could not have written this book without the help and support of many other people.

First of all, I would like to thank my wife and friend, Karen Ande, for giving me her love and support while I was writing this book, and for putting up with significant reductions in our ability to travel and socialize together.

I thank my mother-in-law, Dorothy Hadley, for always asking, whenever she called in late 1998 and 1999: "How's the book going?" I thank my father, Ben Johnson, for helping me to develop an analytic and critical mind and an ability to express myself in writing.

I am grateful for the willingness of several software developers to usability-test earlier versions of this book and give me their frank feedback. The ways in which their feedback helped improve this book are described in the Appendix: How This Book Was Usability Tested. The programmer-testers are Pat Caruthers, Brent Emerson, Stuart Ferguson, Mair Howard, and Sandi Spires.

The book was greatly improved by the comments and suggestions from several reviewers: Stuart Card, Tom Dayton, Jonathan Grudin, Deborah Mayhew, Bonnie Nardi, Jakob Nielsen, Terry Roberts, and Terry Winograd.

The book also was helped immeasurably by the care, oversight, excellent lunches, layout and organization advice, legal advice, excellent lunches, logistical support, nurturing, and excellent lunches provided by the staff at Morgan Kaufmann Publishers, especially Diane Cerra, Belinda Breyer, Edward Wade, and Marilyn Alan, and copyeditor Ken DellaPenta, and illustrator Cherie Plumlee. And did I mention those excellent lunches?