Designing human-computer interfaces is still an art, learned best by creating many interfaces and carefully observing how real users interact with them. However, there are many tools from cognitive psychology that, if understood and applied, can yeild at least two benefits. First, by learning what is known about how humans operate, you can avoid many pitfalls in design. Second, you can make quantitative design decisions.
This book, though nearly 20 years old, contains much essential material that is unknown to many practitioners in the field! If you are designing interfaces, on the Web, for PCs, or for information appliances, you should read and understand the basic material in this book, which can never go out of date as long as humans use keyboards and mice with their hands and scan the screen with their eyes.
My own recent book, The Humane Interface, is -- in many aspects -- just following in the footsteps of this pathbreaking, pioneering, and important work.