For Black librarians, Helton notes, the work of cataloging often meant “countercataloguing.” As Black collections moved from private homes to institutions, quirky personal systems (Schomburg had shelved his own books by color and spine-height) no longer sufficed. But neither, some librarians found, did the purportedly “scientific” information systems used in most libraries, which allowed limited space for non-European subjects.

Today, Porter, who became the chief librarian of Howard in 1930, is remembered as the pioneering architect of one of the world’s premier Africana research centers, who hunted down forgotten manuscripts and built connections between the African American experience and global Black networks. But building Howard’s collection — and making it useful to users — also meant doing battle with inadequate classification systems.

Working with Latimer and others, she tweaked the Library of Congress’s standard subject headings, adding ones for subjects like passing, Pan-Africanism and the blues. She also took on the racism baked into the Dewey Decimal Classification system.

That system, first devised in the 1870s, divided the world — and all knowledge of it — into categories of race, culture and religion. In practice, it wedged all of Black experience into a tiny numerical slice of the universe.

In most libraries, Helton notes, librarians tended to shelve everything Black, whether works of poetry or sociological texts, into two locations: 326, for “slavery,” and 325.26, a subclassification of “colonization and migration” dedicated to “the Negro question.”

Porter started tweaking the system, in ways that also powerfully reconceptualized the world. For example, under the Dewey system, American history was organized largely around wars and presidencies. But Porter rethought that approach, replacing Andrew Johnson’s presidency into “emancipation,” Rutherford B. Hayes as “Ku Klux Klan,” and so on.