Although Universal Principles of Design was published in 2003, I'm embarrassed to admit that I only learned about it recently via Amazon's related books feature. Embarrassed, because it's simply the best book I've read on general design and usability principles in terms of both its content and its presentation.
From its lack of publicity and academic-textbook style cover, one might overlook this book or assume that its content would be dull and dry. But open up to any part of the book and you will quickly grasp its quality. 100 diverse design principles - from human computer interaction, aviation, biology, mathematics, gestalt psychology, etc. - are each presented on their own two page spread. The left page provides the background information and concepts, the right side provides illustrations of examples.
For example, designing for the principle of "Forgiveness" (avoidance and support for errors) includes descriptions of various design methods for forgiveness, such as reversibility of actions and warnings. Illustrations include examples from software, road signs, and mechanical devices. This type of diversity and balance of examples from across human experiences is rare in a book - most tend to focus on a particular area, such as just software. I found myself learning new things as well as affirming my existing knowledge from my own education and experiences.
On a personal note the book's most enduring effect will likely be its influence on my vocabulary. Terms such as "aesthetic-usability effect" and "cost benefit analysis" have now become part of my everyday vocabulary, whereas before I used less articulate terms to discuss these key design principles. In fact the book itself is a fine example of the aesthetic-usability effect.
If there is a criticism of this book it may be in the choice of the 100 principles. The authors admit that there are far more than 100, but they had to compromise for practical reasons. Given that, I wonder why certain oddities made it in, like the "Baby-Face Bias" (characteristics assigned to certain facial characteristics). On the other hand, it is principles like that which give the book is breadth and diversity and I shouldn't expect every principle to be applicable to my own work. Certainly the majority of principles are useful and applicable.