Building products and services that people interact with is the big challenge of the 21st century. Dan Saffer has done an amazing job synthesizing the chaos into an understandable, ordered reference that is a bookshelf must-have for anyone thinking of creating new designs." - Jared Spool, CEO of User Interface Engineering Interaction design is all around us. If you've ever wondered why your mobile phone looks pretty but doesn't work well, you've confronted bad interaction design.

But if you'v...