I read it last fall. It is a fantastic book. It is a bit dry, but that is due to the subject matter being covered and not the author's fault. It is footnoted to a tee, and clearly brilliantly researched.
It covers how violence was introduced to hockey, how the originally nonexistant gap between management and players became as large and defined as it is now, how the various leagues reformed strategically numerous times, and how the NHL ultimately gained full control of the stanley cup and made leagues like the AHA their humble minions.
When you're done that one, check out "Deceptions and Doublecross: How the NHL conquered hockey" by Holzman and Nieforth.