The law of diminishing returns can arguably be applied to historical research as well as larger economic enterprises. What had previously been described in a few paragraphs and notes of such standard works as those by Paul O. Rave and Hildegard Brenner has now been brought to the light of day in a full monographic treatment of Bettina Feistel-Rohmeder and the Deutsche Kunstgesellschaft (German Art Society). For those attracted by the majestic sweep of Joan Clinefelter's book title, however, a more accurate (if still overstated) description is found in the title of her 1995 Indiana University doctoral dissertation, “The German Art Society and the Battle for ‘Pure German’ Art, 1920–1945.”