‘Start with Why’
The core idea of the book is really solid – potentially game-changing, really – but it’s not a book-sized idea. After the first couple of chapters, ‘Start with Why’ became something of a study in belaboring the point. It had the feel of a long talk/short seminar that someone pressured Sinek into converting into book form.
Another note: the book suffers from the malady (common in the ‘business book’ genre) of having its illustrations and examples become very dated very quickly. The inclusion of some examples (and the omission of others) kept undermining the message (which, in its defense, is rather timeless).
tl;dr Save some time and watch Sinek’s TED talks instead: https://www.ted.com/speakers/simon_sinek