The Library of Congress archives 595,000 items in the Carl Sagan papers collection. The figure comes from the collection’s official finding aid, which measures the archive as a large body of correspondence, manuscripts, photographs, audiovisual material, and digital files.
The papers document Sagan’s work as an astronomer, author, educator, and public intellectual. They also preserve material connected with his collaborations with Ann Druyan, including books, television projects, films, and scientific communication. The finding aid lists thousands of containers alongside the item count, showing that “items” is an archival measurement rather than a count of only letters or manuscripts.
A common mix-up is treating 595,000 as the number of pages or as a count of Sagan’s published works. It is neither. It is the reported extent of the Library of Congress collection, which includes many different formats and types of records.