To the average person, Mark Russinovich is as obscure as the fourth Osmond brother. But to IT folks, Mark is every bit a hero as Wozniak, Gates or Ken Olsen.
Mark is also an example of Microsoft's thick skin. Where some take criticism personally, I've found Microsoft to be eminently even-handed. Heck, the company still talks to me!
Russinovich was a thorn in Microsoft's side for years. A security guru, Mark publicized Microsoft security flaws. And in the early days of Windows NT, he proved that NT Workstation and NT Server were essentially the same -- something Microsoft denied at the time but later came to embrace and even brag about. But Mark's company Winternals was so good, and the Russinovich mind so compelling, that Microsoft bought both. Now Mark is a Microsoft fellow and a newly published novelist with his "Zero Day."