Further along, Karmin rightly underscores the historic nature of President Nixon's break from the Bretton Woods agreement, as the postwar monetary framework was known. Until 1971, other countries could exchange dollars for gold, which checked the Fed's ability to print too many greenbacks. When it began to do just that, dollars poured in from overseas, especially from Charles de Gaulle, the vainglorious French president who resented the dollar's preeminence. Nixon, relying in part on a then-unknown Treasury official named Paul Volcker, closed the gold window that year. From then on, since no gold would be forthcoming, the dollar, according to Karmin, would be backed by "faith." This makes it sound quasi-religious, though the basis of that faith is simply a belief in the dollar's purchasing power—in the ability of the U.S. economy to produce desirable goods and services. Interestingly, though the dollar plummeted in the 1970s, the French and everyone else went right on using it.

Karmin condenses this history into a single breezy chapter; the other chapters constitute a "scenic tour" that is ostensibly meant to enlighten us as to the dollar's shaky condition and explain the extent to which the dollar's ubiquity "drives" the globe's prosperity. Let us consider the latter idea. After admitting that factors too numerous to name are responsible for the boom in world trade, Karmin posits that none of them "would have mattered much if the world did not have a currency for conducting international business." Here, our protagonist, the Dollar, presides at the center of things. It is an oversize role. OPEC could price its oil in yen or, for that matter, in drachmas, if it chose to, and people would still buy the stuff.

And Karmin is not really so worried about people abandoning the dollar now. He notes that if central banks were to engage in wholesale selling, they would devastate the value of their own reserves.

Karmin's other chapters look at people, institutions, and countries that are variously involved with the dollar. He travels to Ecuador, which abandoned its hyperinflated currency in 2000 and adopted the U.S. dollar. (Interesting that it could do so without permission from Washington.) He talks to an official at the Bureau of Engraving and Printing, details some plots to steal from the mint that were ultimately foiled, and profiles John R. Taylor Jr., a foreign-exchange trader.

Each of these stories is well reported, though the account of Taylor, who is obsessed with the sort of fleeting gossip that affects markets on only a minute-by-minute basis, strikes me as superficial. "The name of the game," Karmin quotes Taylor as saying, "is to walk as close to the cliff as possible." Whether for walking or investing, this is singularly bad advice. Moreover, by focusing on Taylor's fascination with market rumor, Karmin obscures the fact that, over time, it is the relative strength of international economies that determines currency values.

My larger criticism is that these stories do not quite overcome the book's randomness. Mark Twain said a biography is but the clothes and buttons of a man. Perhaps that is not always the case, but here, although Karmin has dressed up the dollar, I am not sure that he has written its biography.