Adobe InDesign is a digital desktop publishing layout software, similar to QuarkExpress. It is used for basic "prepress" formatting or page layout, of everything from 4-color brochures, to magazine and newspaper advertisements, to entire books and documents.
When I taught Desktop Publishing at Silicon Valley College in the spring of 2005, I built a website to accompany the course. You can see it by clicking on the InDesign flash screen at right.