For a small book, Curious Currency delivers a lot to think about. You may know that Roman soldiers were paid partially in salt; and that is the basis of the modern “salary” as payment for labor. But did you know that salt caravans still cross the Sahara, often in trucks, but just as often still by camel? We all call it “coin collecting” even though numismatics is the art and science that studies all of the forms and uses of money. This dense little book is about the forms that money has taken over the thousands of years of human society. As a medium of trade among humans in society money came before civilization. Of necessity, this is a broad topic, potentially encyclopedic in scope. Robert Leonard makes the information load manageable by wrapping the stories and narratives into convenient chapters based on those broad themes. Curious Currency: The Story of Money from the Stone Age to the Internet Age; 2ndEdition by Robert Leonard, Whitman Publishing, 2019; 153+vi pages; $16.95. After an introductory overview, the chapter titles are Raw Materials, Useful Articles, Ornaments, Customary Objects, and Money Substitutes. Coins fall under “raw materials” because they were valued as metal. But silver, gold, copper, bronze, and iron must take their place alongside obsidian, and flint, which also were money. Whiskey, tobacco, tea, cocaine, and postage stamps are considered “useful articles.” Beads of coral, jade, glass, clam shells, cowry shells, silver, and turquoise join arm rings, neck rings, anklets, and many kinds of necklaces are “ornaments” of course. It seems that almost anything can be used as money. How these were or are used only underscores the broad extent of society and culture. Therefore, it may be perfectly fine that the book closes with examples of “nothing” as money: RFID transceiver chips that you wave at a gasoline pump, cellphones as proxies, and cryptocurrencies bring the reader near to—but not at—the end of the story of money.