Brené Brown - The Power of Vulnerability
Simon Sinek - How Great Leaders Inspire Action
Liz Wiseman, Multipliers: How the Best Leaders Make Everyone Smarter
Julie Zhuo, The Making of a Manager: What to Do When Everyone Looks to You
Simon Sinek, Leaders Eat Last: Why Some Teams Pull Together and Others Don't
Patrick Lencioni, The Five Dysfunctions of a Team: A Leadership Fable
Brené Brown, Dare to Lead: Brave Work. Tough Conversations. Whole Hearts.
Daniel Goleman, Emotional Intelligence
Edward de Bono, Six Thinking Hats
How to Win Friends and Influence People, Dale Carnegie
The Lean Startup by Eric Ries
Better Managers = Better Business, by Pete Fullard
Harvard Business Review (a wide range of leadership thinking)
David Clutterbuck (a good resource for coaching and mentoring thinking)
William Buist: Intentional Mastery