Users who prefer the Micro Soft Windows Excel program should use the data files set up as .XLS files. If you have the CD that came with the book, unzip the file excel.zip using WinZip or PKUnzip to get all the data files in the form DATAX-Y.XLS. You should then move them to the appropriate directory for loading with Excel. If you don't have the CD, you can download excel.zip from the internet.