As the largest single archival collection ever acquired by the Getty Research Institute, the Harald Szeemann Archive and Library is an essential and significant resource for the study of 20th century art and art history. Perhaps the most famous curator of the post-World War II era, Szeemann was an ardent advocate of modern and contemporary art, from Dada, surrealism, and futurism, to conceptualism, postminimalism, performance art, and new forms of installation and video art.

The Harald Szeemann Archive and Library contains a comprehensive record of Szeemann's correspondence with major artists, curators, and scholars from the late 1950s until his death in 2005, as well as significant collections of material from the early 20th century. It encompasses approximately 1500 linear feet of archival research files, containing letters, ephemera, prints, drawings, floor plans, date books, videotapes, and a complete photographic record documenting Szeemann's projects and the artists with whom he was associated.

Additionally, the collection includes Szeemann's extensive library, which comprises rare monographs, artists' books, and limited edition publications, as well as specialized collections on topics ranging from anarchism, science fiction, and pataphysics to other lesser-known artistic movements.