Internet Explorer and the CSS Box Model
http://www.456bereastreet.com/archive/200612/internet_explorer_and_the_css_box_model/

Johansson, Roger
456 Berea Street
2006

Abstract:

One of the differences between Internet Explorer and standards compliant Web browsers that cause a lot of trouble for CSS beginners is the CSS box model. Since the box model is what browsers use to calculate an element’s total width and height, it is quite understandable that different browsers producing different results can be both confusing and frustrating.