John Walkenbach, a.k.a. Mr. Spreadsheet, is arguably the world's foremost authority on Microsoft Excel. His fifty-plus Excel books include Excel 2013 Power Programming with VBA, Excel 2013 Formulas, and the bestselling Excel 2013 Bible, all published by Wiley. He has also written hundreds of articles and software reviews, and created the award-winning Power Utility Pak add-in for Excel.
John lives in Tucson, Arizona. He also plays the banjo - but don't let that prevent you from buying his books.