Benjamin Graham was an influential investor whose research in securities laid the groundwork for in-depth fundamental valuation used in stock analysis today. His famous book, The Intelligent Investor has gained recognition as the foundational work in value investing.There are three core concepts, : you’re not buying a stock, you’re buying a business; you have Mr.Market who has all sorts of mood swings and you want to take advantage of Mr.Market when he’s depressed to buy and euphoric to sell; and the third is margin of safety, which is trying to buy things significantly below what they are worth.So Graham's three key ideas are : 1) Looking at stocks as part of a business 2) Mister Market (subject of this site) 3) Margin of Safety