In the 1890s, the library developed the Library of Congress Classification System. It is still used today to predictably manage millions of items in libraries worldwide.

Object Details Author Library of Congress Subject Cataloging Division Notes "The additions and changes in Class Q, adopted while this work was in press will be cumulated and printed in List 234 of LC ...

Object Details Author Library of Congress Subject Cataloging Division Notes Kept up to date by the division's L.C. classification--additions and changes, and by an irregular cumulative publication ...