Theodore de Laguna (1876-1930) was a professor of philosophy at Bryn Mawr College for 23 years and an author. The Theodore de Laguna collection, dating from 1896 to 1989, contains diverse writings and annotated books by de Laguna. This collection focuses mainly on de Laguna's manuscripts, off prints, and poetry, but also contains original musical arrangements, annotated works by others, and correspondence regarding de Laguna's death in 1930.