" It will also tell you how easy it is to do just that: simply buy the entire stock market. Then, once you have bought your stocks, get out of the casino and stay out. Just hold the market portfolio forever. And that’s what the index fund does. This investment philosophy is not only simple and elegant. The arithmetic on which it is based is irrefutable. But it is not easy to follow its discipline. So "

― John C. Bogle , The Little Book of Common Sense Investing: The Only Way to Guarantee Your Fair Share of Stock Market Returns