THE CAT IN the Hat puts to rest any notion that money grows on trees in this super simple look at numismatics, the study of money and its history. Beginning with the ancient practice of bartering, the Cat explains various forms of money used in different cultures, from shells, feathers, leather, and jade to metal ingots to coins (including the smallest—the BB-like Indian fanam—and the largest—the 8-foot-wide, ship-sinking limestone ones from the Islands of Yap!), to the current king of currency, paper.