Freakonomics - Steve Dubner
Scaling Up, by Verne Harnish
Better Managers = Better Business, by Pete Fullard
McKinsey Quarterly (a wide range of leadership, management and strategic thinking)
David Clutterbuck (a good resource for coaching and mentoring thinking)
William Buist: Intentional Mastery
Stephen Covey: The 7 Habits of Highly Effective People
R. Michael Anderson: Leadership Mindset 2.0
Penny Mallory: Develop Mental Toughness
Nick Howell: Great Coaching Questions
Julie Starr: The Coaching Manual
John Kotter: Leading Change
Caspar Craven: Be More Human
The Five Dysfunctions of a Team: A Leadership Fable by Patrick M. Lencioni
Energy Leadership: The 7 Level Framework for Mastery in Life and Business by Bruce D Schneider