The Design of Everyday Things
Anyone who designs anything to be used by humans--from physical objects to computer programs to conceptual tools--must read this book, and it is  an equally tremendous read for anyone who has to use anything created by another human. It could forever change how you experience and interact with your physical surroundings, open your eyes to the perversity of bad design and  the desirability of good design, and raise your expectations about how thingsshouldbe designed.