Even the smartest among us can feel inept as we fail to figure out which light switch or oven burner to turn on or whether to push pull or slide a door. The fault lies in product design that ignore the needs of users & the principles of cognitive psychology. A bestseller in the United States this bible on the cognitive aspects of design contains examples of both good & bad design & simple rules that designers can use to improve the usability of objects as diverse as cars computers doors & telephones.