The "Catalogue of rare books on slavery and negro authors on science, history, poetry, religion, biography, etc."
He helped found the Afro-American Historical Society that included his personal collection of books, pamphlets, and other materials related to African Americans and the antislavery movement.
He died of a heart attack on June 10, 1910 and his funeral was held at 1115 Lombard Street, his final place of residence.
[6][7][1] In 1906 Robert Adger sold his books to Ella Smith Albert who was the second black student to graduate from Wellesley College.
There have been attempts to retrieve these volumes and those that are found are housed separately at the Wellesley College Rare Book Room.