Piper's notes on Western ballads, with music for some; other folk materials including rhymes, riddles, games, folk sayings, quadrille calls, slang, superstitions, and folk remedies.

Poet (numerous books from Worn Earth, 1932), editor of the O. Henry Prize Stories, 1954-1959, director of the Iowa Writers' Workshop, 1941-1967, and co-founder and director of the International Writers' Program, 1967-1976 at the University of Iowa. Literary manuscripts, correspondence, subject files, and student works documenting his career as a writer and teacher.