This book is pretty much just as the title says. It's a self-onboarding guide for people moving into a new leadership position. At this, I felt it was both too detailed and not detailed enough.
It was too detailed in that there were many detailed plans that seemed like they may fit certain situations, but definitely not others. It was not detailed enough in that many steps in the plans were distressingly high level.
A couple of minor gripes: this falls into the category of business books that comes up with an acronym for everything: P3 = People-Plans-Practices. 5Cs = Customers, Collaborators, Capabilities, Competitors, Conditions. BRAVE = Behaviors, Relationships, Attitudes, Values and Environment. ADEPT = Acquiring Developing, Encouraging, Planning and Transitioning. And so on.
Also, the book really seems aimed at new hires. There is an appendix about promotions and lateral moves within the same company, but the book gives short shrift to items like overlap with the current manager, solving pre-existing trouble, or overcoming your past history. (It touches on some of them, but very superficially.)
Overall, there was some good info here, especially the bit about how there are really only three interview questions*, but I felt that this book was aimed much more at newly hired executives and not as much at promoted mid-level managers (which is what I was hoping for). Might be good for you, less so for me.