1. Buffett, The Making of an American Capitalist by Roger Lowenstien
2. The Intelligent Investor, by Benjamin Graham.
3. Security Analysis, also by Ben Graham
I earned an MBA, CFA and worked on wall street 'valuing companies.' I thought the experienced people around me knew what the f*ck they were doing, but they didn't. These three books will teach you 90% of what you need to know. Lots of other texts/approaches can lead you astray.