Gary Gach does a good job of discussing the basics of Buddhism - the Three Jewels, the Eightfold Path, etc., but once he delves into the various branches of Buddhism and the different ways of meditating, he gets pretty vague and gets very annoying with the silly jokes. A much better book is "Buddhism for Beginners", written by a Tibetan Buddhist nun. It's clear, consise, and doesn't get bogged down in a lot of Sanskrit or Pali terminology that only confuses the beginner. The question and answer format is full of excellent analogies.
As for the other books in the Complete Idiot's series, I read the one on Islam and it is EXCELLENT. Reading this volume after the Islamic book was a big disappointment.
Initially, I had great skepticism - c'mon a "Complete Idiots" book to get me started down the Buddhist path? Really? It just seemed so...so...*American*. But, I had to start somewhere, and my good friend Ben recommended it to me, so I gave it a shot. Now, having finished the book, I realize I owe both my friend and Gary Gach an immense debt of gratitude - this book is really amazing.
One problem I (and many others) have had with other beginning Buddhism books is that the format isn't one that's easy to soak up; the flow isn't as logical as this one's, or not enough detail or context is given to drive points home to a more understandable place. Gach has done a phenomenal job of keeping things simple enough not to overwhelm a newcomer, yet goes into enough detail to keep things interesting and real.
Gach goes beyond teaching the basic belief system into giving examples of how to apply what we've learned in real life, and where else to look for more information. He offers dozens of anecdotes, many koans, a plethora of historical tales and data points, a glossary, and a multitude of other items. One small criticism I have of this book is that he very often doesn't cite his sources when giving statistics.
Throughout the book, Gach returns to important concepts, but not in a manner which I found to be condescending at all - it was merely helpful to be reminded of X, Y, and Z at certain points throughout the book, because they were important to the current subject. The author gives the reader a very solid foundation to build his or her beliefs upon, should the reader desire, including a rich and detailed historical background of Buddhism throughout the world.
I will be unreservedly suggesting this book to anyone who expresses an interest in this spiritual path.