Once upon a time, Microsoft and IBM were working on OS/2 2.0 together. OS/2 was going to replace DOS and Windows.
But then..in the middle of this, a gifted engineer at Microsoft figured out how to get Microsoft Windows to run multiple DOS sessions at once (that could be multitasked together) and figured out how to get Windows programs to run in protected mode (i.e. breaking the 640K barrier). By figuring that out, Windows 3.0 was made and so was history.
Eventually OS/2 was wiped out by Windows and today, most of us are running Windows XP. But without the contributions of David Weise, the computing world would likely be very different (and for the worse) today (though I wish OS/2 had won out, I don't think OS/2 2.0 would have been nearly as good if it weren't for Windows 3.0).