The Economics Focus column near the back of the Feburary 11th edition of The Economist recommends a new book called The Theory of Corporate Finance by Jean Tirole. The article argues that corporate financial structure (equity vs. debt) does matter, but more deeply, shows that the separation of interests between company agents (officers) and owners (shareholders) carries risks and costs about which economics so far understands very little. In this era of smug, overpaid executives, formalization and publication of the failure of this compensation to align with owner interests stands as a gratifying initial step toward making it stop.