'Business' is a large topic - anything in particular? Marketing? Finance? Customer Development? Management? etc?

Books that I'd recommend: Anything by Peter Drucker, The Five Dysfunctions of a Team by Patrick Lencioni, Made to Stick by the Heath Brothers, Blue Ocean Strategy by Kim and Mauborgne, among others. I'm sure plenty others here will also give you other recommendations that seem more 'start-up' like too.