It's difficult to find the history of the IntelliMouse, but it looked like the original one launched around 1998 had the scrollwheel and a mouse ball, but the s

It's difficult to find the history of the IntelliMouse, but it looked like the original one launched around 1998 had the scrollwheel and a mouse ball, but the second generation one has the optical addition. Not sure when it launched though. According to this site: http://www.oldmouse.com/mouse/microsoft/ http://www.oldmouse.com/mouse/microsoft/ it's around 1999. But there is no attribution or month listed. This was for the 1.0 version though, that was quickly discontinued. 1.1A launched as a minor hardware revision later, and the first reliable one seems to be the 3.0 from forum posts on the subject, which dropped around 2001-2002. The history of the Apple Pro Mouse is super-easy to find though, it launched in July 2000. So sayeth Apple-History and MacTracker. Looks like MS was first to market but with a fairly flaky original and refined it on the market.