Reading a book about management isnt going to make you a good manager any more than a book about guitar will make you a good guitarist, but it can get you thinking about the most important concepts.
I'd be like, alright, I don't know anything about sales. So I would search for sales on Amazon, get the three top-rated books and just go at it. I did that for marketing, finance, product, engineering. If there was one thing that was really important for me, that was it.