NOWADAYS MONEY SEEMS to have become a pure idea, a universally agreed-upon fiction conveyed by pieces of paper, plastic cards, computers, and coins made of nearly worthless metal. But until just fifty-one years ago, money meant solid gold, that precious, rare, beautiful, glamorous, and nearly indestructible element which had stood throughout history as the invulnerable guarantee of financial security. For 138 years, from 1795 through 1933, the United States grounded its currency in gold (as well as silver part of the time) and issued hundreds of millions of gold coins, valued at one to twenty dollars apiece. They were worth their weight and were traded freely. Today most of them are gone—they were melted down for bullion, both by citizens and by the government.