He co-founded the Library of America, and served as chairman of its board. He was the Marius Bewley Professor of American and English Literature at Rutgers University. He was also the editor of Raritan, a literary quarterly, and an editor of Partisan Review. He was series editor of Prize Stories: The O. Henry Awards from 1961 to 1966.
In 1968, he signed the “Writers and Editors War Tax Protest” pledge, vowing to refuse tax payments in protest against the Vietnam War.
- Stories British and American (1953) with Jack Barry Ludwig
- The Comic Sense of Henry James: A Study of the Early Novels (1960)
- In Defense of Reading : A Reader's Approach to Literary Criticism (1963) editor with Reuben A. Brower
- A World Elsewhere: The Place of Style in American Literature (1966)
- American Literature: Volume Two (Little, Brown 1970) editor with William L. Vance
- The Oxford Reader: Varieties of Contemporary Discourse (1971) editor with Frank Kermode
- The Performing Self: Compositions and Decompositions in the Languages of Contemporary Life (1971)
- Mailer (Fontana Modern Masters, 1972)
- Robert Frost: The Work of Knowing (1977)
- The Renewal Of Literature: Emersonian Reflections (Random House, 1987) ISBN 0-394-50140-3
- Raritan Reading (1990) editor
- Ralph Waldo Emerson (1990)
- Poetry and Pragmatism (1992)
- Collected Poems, Prose, and Plays of Robert Frost (Library of America, 1995) editor with Mark Richardson
- Trying It Out in America: Literary and Other Performances (2003)
- Mack, Arien (Editor) (Autumn 1988). "IN TIME OF PLAGUE THE HISTORY AND SOCIAL CONSEQUENCES OF LETHAL EPIDEMIC DISEASE". Social Research. 55 (3). Retrieved 10 March 2011.
- “Writers and Editors War Tax Protest” January 30, 1968 New York Post