Greenblatt distills value investing into the 'Magic Formula': rank by earnings yield and return on capital, buy the top-ranked, hold for a year, repeat. Simple enough for a child to follow, yet it historically outperformed the S&P 500 by a wide margin. The reason it works is the reason most people won't follow it — it requires patience during the inevitable stretches when it underperforms.

The case for it, the case against, and the rest of the canon open with Pro.