Addison-Wesley Signature Series (Cohn) Ser.: Essential Scrum : A Practical Guide to the Most Popular Agile Process by Kenneth Rubin (2012, Trade Paperback)
Whether you are new to Scrum or years into your use, this book will introduce, clarify, and deepen your Scrum knowledge at the team, product, and portfolio levels. Kenny Rubin has created an indispensable resource for us.