Previously presented as a feature on the Corcoran Gallery of Art website from 2011 through September 2014, this scholarly apparatus contains in-depth research and documentation for each of the 102 paintings highlighted in the accompanying volume Corcoran Gallery of Art: American Paintings to 1945. These works are among the nearly 9,000 Corcoran works that have been accessioned by the National Gallery of Art. The apparatus provides provenance, exhibition history, published and unpublished references, technical notes, and data on related works, and is a significant resource for art historians, educators, and the general public. The extensive research on these paintings resulted in recovering more than 50 original titles, dates, and attributions, and filling in numerous provenance gaps. While this information was kept up to date through 2014, more recent research on each work can be found on the collection pages of the National Gallery of Art website. (When the Corcoran Gallery of Art closed in 2014 the National Gallery of Art accessioned much of its collection and became custodian of its publications. This and other out-of-print Corcoran volumes have been made freely available as PDFs in an effort to perpetuate the legacy of that institution.)