An old one, but I think a good one - What Color Is My Parachute? It’s intended for finding a job, but it’s kinda a whole life thing too. If I remember correctly, it was written by a guy who was studying for the priesthood and then realised it wasn’t for him - but he really didn’t know what *was* him, what he could do or might do something or anything. I don’t suppose the thing about confidence, and this book is, the goal is to find out who you are and then be it on purpose… (!)