This chapter sketches three stages of the relationship between commerce and museums and offers a rough-and-ready three-part taxonomy of that relationship. It focuses on American art museums. The chapter elaborates on one major difference between European and American museums. American art museums incorporated what one would call 'decorative' arts into their collections from the very beginning: textiles, ceramics, furniture, wallpaper, silver. It proved a short step, therefore, to move from promoting commerce outside the museum to bringing commerce directly inside the museum, though the move had to wait nearly fifteen years because of the Great Depression and the Second World War. In 1987 the Metropolitan Museum of Art opened a branch in Stamford, Connecticut, an affluent suburb of New York City. There, wealthy shoppers could purchase replicas of Etruscan earrings, reproductions of eighteenth-century candlesticks originally made in New Jersey, and dinnerware copied from seventeenth-century Chinese ceramics. Keywords: American art museums; commerce; decorative arts; European museums; Great Depression; Metropolitan Museum of Art