When a system administrator writes a script, it behooves us to make it simple to use and simple to understand. If we write utilities for users, it is even more important to get the user interface right. Making the interface simple, understandable, and yet powerful can be daunting.
This book does an excellent job of introducing us to the challenges (and, indeed, the joys) of making the interface easy for normal human beings to use. This, in turn, will reduce the number of human errors that happen – human error is the number one cause of system failures. It will also introduce you to the fact that a lot of what passes for “difficult to use” is actually design failures in the interface.