Reed College’s archives have turned up a true gem of 20th-century poetry history, a high-quality recording of Allen Ginsberg reading his epochal long poem, “Howl,” that was taped a few months before it was published and became the subject of a landmark obscenity trial.

The recording was made on reel-to-reel tape in front of a group of students in a Reed dormitory lounge in February 1956, during Ginsberg’s visit to the college on a hitchhiking trip with a fellow poet, Gary Snyder, a 1951 Reed graduate.

Mark Kuestner, a special-collections librarian at Reed, and John Suiter, a Boston-based literary scholar, discovered the tape last summer in Reed’s archives while Mr. Suiter was preparing a biography of Mr. Snyder, who is an emeritus professor of English at the University of California at Davis. Ginsberg died in 1997.