It's easy as a technical employee -- developer, architect, administrator -- to know your job much better than your boss. Once you've reached that point, it's equally tempting to believe you know *more* than your boss, and to question why they insist on continuing to waste your time.
This book is an excellent first step in explaining what it is managers are supposed to be doing, and what it is that management is supposed to accomplish with the standard management tricks -- meetings, one-on-ones, reviews -- that can seem like such a waste of time when all you want to do is write good code. Even if you never want to go into management yourself, but especially if you do, it's worth reading.
Plus, the book is an easy, engaging read that makes a lot of sense even the first time through.
Highly recommended.