This book was used in both my undergraduate and graduate courses in artificial intelligence. It is a very readable book, and an enormously useful reference. I believe they at least do a cursory overview of the most critical concepts in AI, and if they don't, there are usually great references at the end of the chapter.That is actually my favorite features of this book. At the end of each chapter, Norvig and Russell will give something like an annotated bibliography, but with much more depth.