John Walkenbach aka "Mr. Spreadsheet" is the principal of J-Walk and Associates, Inc. and a Microsoft Excel MVP. He is a leading authority on spreadsheet software and the creator of the award-winning Power Utility Pak. John has written more than 50 books, as well as articles and reviews for publications including PC World, InfoWorld, and Windows. He also maintains the popular Spreadsheet Page at spreadsheetpage.com.