This paper was first delivered at the conference Art Dealers, America and the International Art Market, 1880-1930 sponsored by the Getty Research Institute, The Getty, Los Angeles, CA, January 2018. The essay is based on research conducted at the GRI Special Collections’s archival holdings of materials belonging to the New York art gallery M. Knoedler & Co. The paper outlines a quantitative methodology for approaching the Getty’s data set, which was created through the transcription of Knoedler’s 11 painting stock books covering the gallery’s operations from 1872 to its closing in 1970. The paper explores the advantages of concentrating on the gallery’s premium picture market and discusses what can and cannot be learned from the information provided by the stock books. It explains why concentrating on the gallery’s purchases rather than sales best reveals the evolving tastes of American art collectors from the Gilded Age to the Depression. Using only Knoedler’s high-end market, the paper demonstrates which artists and kinds of art the gallery most strongly invested in and how these investments changed over time