This book wasn't what I thought it would be about based upon the title. The first section is called "Developing Yourself" and basically outlines various self-improvement topics such as motivation, memory & recall, happiness, time management, etc. It actually references the pseudo "law of attraction" or "the four agreements" so definitely lost some credibility by referencing unproven new age beliefs. He references some material from Stephen Covey's book The 7 Habits of Highly Effective People and generally references other books. Not sure which references are actually backed by science.
The second half of the book has a section called "Managing Others" and has some information that covers the following topics: assertiveness, coaching, communication, conflict management, creativity (brainstorming), giving feedback, goal setting, influence & persuasion, leadership, negotiation, presentation, relationships, and teamwork. Most of the material was information I've read in other self-help/business books. Each "tool" had a quick 2-page summary written about it. If you have never read any of these type of books, you'd probably find this book as a nice guide to provide direction on what to read for a deeper understanding but for me since I've been reading this type of subject matter, it was not really useful.
Chapter 75 - Extended Tuckman teamwork theory was a new theory for me to read about. It was created by psychologist Bruce Tuckman in 1965 who described the four stages every team goes through as it evolves and they are forming, storming, norming, and performing. Ten years later he added an adjourning stage to the model and others have suggested adding dorming, mourning, transforming, and reforming. It's an interesting idea but in my opinion, the key feature seems to be that groups are always in a state of flux. That's not really that profound when you think about it because we are always in a state of change even if we are not aware of it.