Creating Liquid Layouts with Negative Margins
http://alistapart.com/articles/negativemargins/

Brill, Ryan
List Apart, A
2004

Abstract:

Two- and three-column, liquid page designs with header and footer are easy to dash off using old-school HTML table layout methods. Designing them in CSS is trickier, and can sometimes even require you to structure your page’s content elements in a specific (and undesirable) order. Negative margins to the rescue! Ryan Brill whips up two quick CSS layouts to demonstrate the power of negative thinking.