In the late 1920s E.K. Waterhouse embarked on an El Greco catalogue raisonné, a project that occupied him on and off for the following forty years. His notes for this unpublished work, in the Getty Research Institute, Los Angeles, reveal that it occupies an important place in the sequence of El Greco catalogues in the twentieth century, in particular because of its influence on Harold E. Wethey’s standard work of 1962.