David Clutterbuck (a good resource for coaching and mentoring thinking)
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
Nancy Kline: Time to Think
Kate Trafford: Get There, Love Here
Julie Starr: The Coaching Manual
John Kotter: Leading Change
Daniel Kahneman: Thinking, Fast and Slow
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
The Fear-Fighter Manual: Lessons from a Professional Troublemaker by Luvvie Ajayi Jones
High Performance Habits: How Extraordinary People Become That Way by Brendan Burchard