This is a must for technical reference in ATM. To understand ATM, I started by reading this book. Then, I read the ATM traffic management specification in ATM Forum and quite a number of ATM-related papers. However, I still find the book very useful from time to time. It gives summary of different techniques presented in different papers (eg. schedulling mechanism in Chapter 5), and also overview of different parts of traffic management (at the start of each chapter). For beginners, some sections will be quite difficult, because it did get into the details. You just skip it, I think the rest still able to help you understand the traffic management of ATM. I really love this book. :)