I haven't had the chance to read anything in many, many months as I have been working on The Efficiency Playbook
(scheduled to release on July 15th, 2017). Finally I can pick up something and chip away at it each morning, critical to keeping the saw sharp, and the book I am working on now is called Universal Principles of Design.
If you do anything creative, or any type of work, social communication, etc (and that covers most of us), it will definitely be worth your time and investment to read a good book on design. I have purchased and started several, but this is the one the resonates with my style of thinking best. Short, fast, easy to understand chapters, and it is exhaustive in the number of topics covered. It will give you incredible tools to make your work more efficient. This would be a great read after one finishes The Efficiency Playbook.
Homerun - no question. Highly Recommended