I forget the exact background, but MS was at one time working pretty heavily on the Mac interface for Apple. Excel started out as a Mac program, developed by MS, and Gates first big breakthrough was porting Excel to the PC. IIRC, this was when Windows 1.0 was in it's infancy, and Excel 1.0 for the PC came with a runtime version of Windows that loaded to run Excel. Excel destroyed Lotus 1-2-3, which had been the premiere spreadsheet at the time. BTW, Lotus 1-2-3 included the 1-2-3 because it was originally intended to be a spreadsheet, word processor and database.
Other Freeps may have more accurate info, but MS definitely contracted with Apple for development of the graphical interface, then used that knowledge to create Windows.
