What the hell is "offset" ?

What the hell is the offset of a rim? And how does it affect handling and performance? :screwy:

This chart will explain wheel offset:

http://www.midatlanticmotorsport.com/images/web_fitment_chart.jpg

The April issue of Grassroots Motorsports Magazine has an article in the Tech Forum. It's on pages 167, 168, and 170. It covers Wheel offset, track width, steering axis inclination, and scrub radius. If you don't subscribe you could browse through it at a bookstore that sells "Grassroots Motorsports" magazine.