It is the part of a wise man to keep himself today for tomorrow and not to venture all his eggs in one basket.
--Miguel de Cervantes
Nothing can break the law of risk and reward, but a diversified portfolio can bend it. When you spread your money properly among different asset types, a rise in some will offset a fall in others, muting your overall risk without a commensurate drop in return. It's the closest thing to a free lunch there is in investing. To make the alchemy work, you must load up on assets whose up and down cycles don't run in sync: stocks (both U.S. and foreign, as well as large-company and small), bonds (of varying maturities), cash, real estate and commodities.