He's analytical, driven, calculating, irritable, confident, inquisitive, opportunistic, boyish, wealthy, generous, smart, and competitive. Microsoft's cofounder and chairman has been called many things, some flattering, others unprintable.

I've interviewed Gates a half dozen times and found him to be engaging and likeable, though more distant than friendly. He once sat patiently for more than an hour in one of those interviews, well beyond the time allotted, until I finally ran out of questions. He can be testy and evasive, too.

While reporting InformationWeek's cover story, "The Legacy Of Bill Gates," my colleague John Soat and I interviewed people who have known Gates over the years, some personally, others from a distance. Following are some of their observations. Share your thoughts on how Mr. Microsoft will be remembered, or should be remembered, as he shifts gears from management to full-time philanthropy.

"Bill has made a number of contributions to the software industry. The biggest one: the insight that made computing personal. More than anybody else, Bill recognized that there was an enormous amount of computing that could be done on the desktop on industry standard hardware and software, and by playing off that standardization, deliver an incredible level of functionality to the user."
John Swainson, CEO of CA

"Bill Gates is the proxy for how Microsoft will be remembered. First and foremost, he's a businessman. He's not an inventor or technologist, per se, and I don't think he would claim to be. He's fundamentally a geek."
Greg Papadopoulos, CTO of Sun Microsystems

"Pound for pound, he's the most controversial figure in IT."
Rich Powers, director of advanced technologies with FMC

"He has this ability to know if somebody is shooting him a pile of malarchy. He could drill right into the weakness in a presentation. Sometimes it would be on an arcane piece of technology. Almost immediately he would pick up on where to drill in with questions."
Michael Cherry, analyst with Directions On Microsoft and former Microsoft employee

"I'm a huge, huge admirer of Gates as a person and his philanthropy. Even though I was an outspoken critic of Microsoft, it's stunningly admirable behavior. That's his legacy."
Mitchell Kertzman, partner with Hummer, Winblad and former CEO of Powersoft, Sybase, and Liberate Technologies

"Bill Gates breaks very complex things into simple, easy-to-understand form. He understands the end result of what innovation and breakthroughs can do."
Bill McDermott, CEO of SAP America

"I think of him as the father of the software business. He's multifaceted. He's interested in how all this gets put together, and an unbelievable businessman. In the IT industry, he's a close friend to all of us."
Ralph Szygenda, CIO of GM

"He will go down in technology history as one of the great businessmen of the era. While Gates could be called a fierce competitor, or even unfair depending on your perspective, it's hard to ignore the benefits that Microsoft brought to corporate productivity or the returns to shareholders."
Jason Maynard, software analyst with Credit Suisse

"Gates built the first software company in the industry, and I think he built the first software company before anybody in our industry knew what a software company was. And that was huge."
Steve Jobs, CEO of Apple, speaking at the All Things Digital conference

"He impeded the growth of the independent software industry. People in the industry don’t think of Microsoft as a company with innovations, they think of them as powerful and successful."
Marty Goetz, co-founder and former CEO of Applied Data Research, one of the first independent software companies

"There are still lessons from what Microsoft has done that, as an entrepreneur, I can’t ignore. Gates proved in consumer software that the best product doesn’t always win—that still holds true in consumer Web apps."
Sean Ammirati, VP of business development and product management for mSpoke Inc.