The Zallen papers specialize in condensed matter research, largely during the second half of the twentieth century. The papers include information concerning Zallen's study at Harvard and his work at Xerox; research notes; professional correspondence; Virginia Tech lectures; drafts of published works; and materials concerning trips, sabbaticals, and conferences. The corporate and governmental institutions with which Zallen worked include: the Office of Naval Research, Raytheon Manufacturing Company, Texas Instruments, and IBM. Materials include hand-written documents, published material, flat plate drawings, photographs, a sample of "melt-spun amorphous," and stamps from various countries. Expanatory notes made by Zallen in 2006 annotate many documents. Some significant documents include supporting patent materials for Spin Coated Photoconductor Films, letters concerning the protest by industrial scientists at Xerox over the escalation of the war in Indo-China, and copies of APS Solid State Correspondence discussing the formation of Solid-State Physics.