The Model M started out as a replacement for IBM's Model F keyboard that was previously bundled with its terminals. For others, including by Bowman's reckoning, it's down to the buckling spring switches inside and their associated qualities. Throughout its life, the Model M went through various changes, especially when IBM sold off a portion of keyboard business to Lexmark in 1991. According to Bowman, Lexmark instructed then product manager of their keyboard business unit, Neil Muyskens, to find a buyer for the keyboard business. I'd probably go as far to say that the Model M is one of the most important, yet underrated, innovations of the twentieth century.