Overall, this is a solid book describing the rise of the Chief of Staff role inside corporations, their various archetypes, and how the role differs from the political role of the same name.
That said, the book leans more towards justifying what use a CEO has for a chief of staff, and doesn't come close to explaining why it seems like every C-level executive these days wants or needs to have their own -- in addition to having an executive assistant. Too often, these chiefs-of-staff get in the way, unnecessarily shielding their executive from really being in the trenches (understanding, operating, and debugging the business) and add little value beyond creating yet another layer of bureaucracy & TPS reporting.
I'm afraid that many C-suite executives reading this little volume will come to the conclusion that they definitely need a chief of staff, as not enough has been done in here to dissuade them from that thought. Parris could have done the world a favor by framing the topic first as a skeptical "why do you need one?" rather than being an unabashed cheerleader for the role, particularly at the CEO-1 level. But of course, given that his consulting practice is based on him creating more chiefs of staff in the world, the incentives don't align for applying more skepticism, which is unfortunate.