Brené Brown - The Power of Vulnerability
Simon Sinek - How Great Leaders Inspire Action
Carol S. Dweck, Mindset: The New Psychology of Success
Julie Zhuo, The Making of a Manager: What to Do When Everyone Looks to You
Patrick Lencioni, The Five Dysfunctions of a Team: A Leadership Fable
Daniel Goleman, Emotional Intelligence
Paul Sloane, How to be a Brilliant Thinker
Paul Sloane, Lateral Thinking for Every Day
Fermat’s Last Theorem, Simon Singh
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)
Harvard Business Review (a wide range of leadership thinking)
David Clutterbuck (a good resource for coaching and mentoring thinking)