Most of the materials are related to a particular book project: drafts, proofs, edits, fouls, markups, correspondence, etc. Note that most projects include both regular size and oversize materials.
Research material for two of Larry Tye's books, Superman: The High Flying History of America's Most Enduring Hero, which includes correspondence, subject files, and legal files, and for Bobby Kennedy: The Making of a Liberal Icon, which includes oral history files and subject files.