Wendy Ball -- co-author with Tony Martin of "Rare Afro-Americana: A Reconstruction of the Adger Library"
Octavius Catto -- close friend of Robert Mara Adger, Catto's funeral in 1871 was the biggest and most elaborate ever held for a black man in America. Robert Mara Adger named his son Octavius Catto Adger (b-1867) after him. Octavius Adger Jr. was born in 1898.
Fanny Jackson Coppin -- teacher at the Institute of Colored Youth which was attended by many of the Adger children.
W.E.B. DuBois -- gives mention to Robert Mara Adger in his book, "The Philadelphia Negro". Chapter 9, The Occupations of Negroes.
Tony Martin -- co-author with Wendy Ball of "Rare Afro-Americana: A Reconstruction of the Adger Library"
Arthur A. Schomburg -- (1874-1938) His collection of Afro-American related books, manuscripts, pamphlets and ephemera was purchased for $10,000 in 1926. It is currently housed in the Harlem branch of the New York Public Library.
William Still -- (1821-1902) Was an underground railroad leader and was Secretary of the Pennsylvania Anti-Slavery Society.
Booker T. Washington -- An Adger Family friend, he is quoted in The Century Magazine article "Negro Homes" May 1908 on the number of books Adger had amassed.