What is the best professional development book you've ever read?

The Leader Who Had No Title The 5am Club Both these books are by Robin Sharma. You can also find many Robin Sharma videos on youtube and he has podcasts. You won't be dissapointed either way, reading his books, watching his videos or listening to his podcasts. I can't reccommend him highly enough. Love to hear your thoughts if you decide to check him out.

@Hope

Only read one, though it's not exactly about professional development, the content is related enough.

Girl, stop apologising - Rachel Hollis