From Amazon.com: The authors present 40 guidelines that cover different aspects of defensive design, or contingency design as they call it. Some are pretty basic, such as "Always identify errors the same way". Others require a bit more thought in the coding of the site, such as "Assist form dropouts by saving information". But instead of just stating the guideline and moving on, they take it a step further. Using familiar and popular web sites, they provide "thumbs up" and "thumbs down" examples of each guideline. By seeing the guidelines actually applied in real-life, you are much more likely to understand the problems associated with it. I know if my site was used as a "thumbs down" example, I'd be motivated to get it fixed post haste. At the end of the book, there is a contingency test you can apply to your site. You start by taking the test yourself as a baseline. After you think you've cleaned up the site, then have some real visitors use the site and take the test. If you can do well in both these scenarios, then your site is better off than most others out there. You're probably also seeing a high rate of repeat traffic. The book is easy to read, but you'll most likely return to the guidelines over and over. This is a book that is going to be no more than an arms-length away.