Born in 1879 in a Black community in Washington, D.C., Belle Marion Greener was the daughter of Genevieve and Richard T. Greener (her father was the first Black graduate of Harvard College). When her parents separated in the 1890s, Genevieve changed the family’s last name to Greene and added the middle name “da Costa”; the light-skinned family began to pass as white. Belle da Costa Greene was educated in library science at Amherst College and took a job at Princeton in 1902, focusing on rare books. In 1905, she went to work as J. P. Morgan’s personal librarian, expanding his holdings of manuscripts and art. (For example, she won William Caxton’s 1485 printing of Mallory’s Le Morte d’Artur at auction—for $41,800.) When Morgan died, in 1913, Greene continued under his son J. P. Morgan Jr., helping to transform his father’s library into a public institution. In 1924, she became the library’s first director, and has since been called “one of history’s greatest librarians” and “the soul of the Morgan Library.” On its centenary, the institution now celebrates Greene’s legacy with an exhibition exploring her life, her genius in her job, and her enduring impact. Expect to see medieval manuscripts and rare printed books, archival records, letters, and portraits. —Jeanne Malle