The 5 Levels of Leadership: Proven Steps to Maximize Your Potential is a gem from John Maxwell. Required reading for every leader
Navigating the Growth Curve is the basis for the Stages of Growth Assessment
The 7 Habits of Highly Effective People: Powerful Lessons in Personal Change. If you have not read this foundational book from Steven Covey, you need to start your personal growth with this one!
The Complete Leader uses the TTI TriMetrix HD assessment that I use to help shape and grow leaders