Interesting theory, you might ask, but does it work?
The book, I think, has two potential audiences. The first is any individual who feels unfulfilled in their job. The second is any people manager / leader.
So I'm reviewing this book a couple of years after reading it, and having had time to integrate its tenets into my work life, and also to examine my level of motivation, and those of my team members.
At a simplistic level, I'm happy when I'm being creative. My team members are happy when I set broad overall goals, but leave them the autonomy to achieve those goals in a creative way (or in a way that builds mastery). Empirically, the book makes sense.
I moved into a new area, where I did not have "mastery" (which (according to Pink) along with autonomy and purpose forms the basic for motivation), and I observed my motivation decrease. So I looked for a small, related area to work on, to develop mastery, and motivation improved (I wanted to go into work again). Yep, the book checks out.
So when evaluating the book, I start with the personal observation that a couple of years implementing the ideas has borne fruit, both for myself and for my team. That accounts for most of the stars.
Some reviewers take exception to the amount of repetition, in that the ideas are so simple that they can be stated in a page (or less, which Pink does), yet Pink takes a whole book, to state them and restate them at ever greater depth. I prefer to commend this approach, on behalf of busy people everywhere who need a quick summary, to inform them what they'll get out of reading this book, but can then go on to explore the concepts and the evidence at a series of graded levels.
So yes, readable, digestible, actionable, challenging and intellectually interesting. This book is all of those.