They don't like the word power. But they are powerful. They don't like being in the public eye. But they can't avoid it. No country in the world has had such an influential family in finance. Nowhere else have so few controlled such a large portion of the stock exchange and had power over so many vital industrial companies: SKF, Saab Scania, ABB, Astra Zeneca, and Electrolux. The patriarch, Peter Wallenberg, is over 80 and still keeps an eye on the business. But since 2006 the empire has been run by his sons, Jacob and Peter Jr, and nephew Marcus. They are the fifth generation. For over a century, the Wallenberg family has crowned the Swedish business world, and they have guarded their private lives just as carefully as they have managed their business.—Ulf Kjell Gür