What's wrong with it? I'm just gathering recommendations myself, and it'd help to know especially if there are more general red flags to watch out for.

The book is completely fine and worth the read! Just know that it's a book to explain the career path of an Engineering Manager in the tech industry.

My criticism is around how often the book is recommended. Many people want to learn HOW to become a manager. Manager's Path doesn't provide that.

Conversely, a lot of people recommend An Elegant Puzzle. Great book, but I would not recommend it to first time managers – it's too advanced.

Elegant Puzzle is for experienced managers, specifically people that are managing Managers. Check it out if you're 2+ years into their management career.