Don't Make Me Think: A Common Sense Approach to Web Usability by Steve Krug
People won't use your web site if they can't find their way around it.
Whether you call it usability, ease-of-use, or just good design, companies staking their fortunes and their futures on their Web sites are starting to recognize that it's a bottom-line issue. In Don't Make Me Think, usability expert Steve Krug distills his years of experience and observation into clear, practical--and often amusing--common sense advice for the people in the trenches (the designers, programmers, writers, editors, and Webmasters), the people who tell them what to do (project managers, business planners, and marketing people), and even the people who sign the checks.
Krug's clearly explained, easily absorbed principles will help you sleep better at night knowing that all the hard work going into your site is producing something that people will actually want to use.