In no particular order:

7 Habits of Highly Effective People – Stephen R. Covey

How to Win Friends and Influence People – Dale Carnegie

Emotional Intelligence – Daniel Goleman

Emotional Intelligence 2.0 – Greaves Jean and Travis Bradberry

Fall in Love with the Problem Not the Solution – Uri Levine

Business Model You - Timothy Clark, Alexander Osterwalder, Yves Pigneur

Start With Why - Simon Sinek

Leadership and Self-Deception - Arbinger Institute

Choose Your Enemies Wisely - James A. Autry

The First 90 Days - Michael D. Watkins