Meet John Bogle, the Jedi Knight of investing

At 80, he says he doesn't get enough done. And while ever more money is moved around the world by legions of finance Ph.D.s, he offers this assessment of investing.

"It's not rocket science."

Meet John Bogle. He's the crusty founder and retired chairman of Vanguard, now the largest mutual fund firm in America, but I prefer to think of him as the Jedi Knight of investing. And the force is with him.

I've called him to talk about the 10th anniversary edition of his classic book, Common Sense on Mutual Funds ($30, Wiley & Sons). Now 600 pages, up from 450 in the first edition, this is the definitive book on index fund investing. It explains why index fund investing is the best way -- no, the only way -- for people to invest their savings.