The more you understand product management, the more you understand how design fits into an organisation, and the better a designer you'll be.
Escaping the Build Trap: How Effective Product Management Creates Real Value
A practical look at the problem with many product organisations, and how product management should work. An excellent introduction to the importance of product management.
Inspired: How to Create Tech Products Customers Love
Where the previous book focuses more on principles, Marty lays out a blueprint for how to successfully approach product management, both at the individual and organisational level. You'll know more than most about product management after you've finished this book.
Sense & Respond: How Successful Organizations Listen to Customers
From the authors of Lean UX, this book takes an organisational view of product management, and teaches you how to change businesses for the better.