It's an excellent book on Bayesian Networks. After reading it I gained a solid understanding on how Bayesian Networks work as well as how to design and use them to solve real probabilistic problems. This book is accompanied by a tool for modelling and reasoning with Bayesian Network, which was created by the Automated Reasoning Group of Professor Adnan Darwiche at UCLA. I'm planning to adopt Bayesian Networks in analyzing betting exchange markets and reading such a great book gave me all I needed to apply Bayesian Networks in my research.