This book has turned out to be the best investment I've made so far in my 20 year IT career. I've always trusted O'Reilly books for their detailed accuracy. However, for the task at hand, I didn't need a book to explain WHY things work... I needed one to tell me how to GET them to work. This book was perfect! It doesn't replace the DNS and BIND, 4th Edition, but is a great compliment... Actually, I'm finding the 4th Edition a perfect compliment to the Cookbook.