Emelie Johnston if you want to go the personal development route, Think and Grow Rich: A Black Choice has had the biggest impact on my life and thought process!
From a business perspective: I would say Built to Sell... it’s a simple read and even though I’m not looking to sell my business it thought me the process of fully fleshing out a service for clients in a consultative way and using that service or product as the anchor to scale my business. Building out a product, not product(s) is the first step to success for small businesses.
As a kicker: if you are in to really understanding the early days after slavery for blacks and how double consciousness played a role in it and still does today. “The Souls of Black Folks” is the way to go. I think every black person should read that book as most of it is still rings true today.