About the Author John Walkenbach is a leading authority on spreadsheet software, and principal of JWalk and Associates Inc., a Southern California-based consulting firm that specializes in spreadsheet application development. John is the author of about 30 spreadsheet books, and has written more than 300 articles and reviews for a variety of publications, including PC World, Info World, PC Magazine, Windows, and PC/Computing magazines. He's currently contributing editor for PC World and writes the magazine's monthly "Here's How" spreadsheet tips column. He also maintains a popular Internet Web site called "The Spreadsheet Page" at www.j-walk.com/ss, and is the developer of the Power Utility Pak, an award-winning add-in for Microsoft Excel. John graduated from the University of Missouri, and earned a Ph.D. from the University of Montana. John's other interests include guitar, MIDI music, novels, digital photography, and gardening.