“The risk you are likely to be rewarded for taking is the risk of owning all stocks. In effect, rather than betting on one roll of the dice, one spin at the roulette wheel, or a single hand at the blackjack table, you can own the whole casino. You can do this effortlessly, cheaply, and reliably by buying a total stock-market index fund, a low-cost portfolio of all the stocks worth owning.”
