When Robert Frost died on 29 January 1963, the public mourned the loss of what it thought was the grandfatherly old bard of the nation, the most beloved poet of the century, the gentle writer of simple nature lyrics. Nothing could have been farther from the truth. Though indeed loved and mourned by his public, Frost was anything but the kindly rural sage he pretended to be. Just as the accessible surface level of his poems hid deeper ambiguities and dread, so the glare of his public career masked the pain of his private life. In the years since his death, biographical revelations and critical appraisals have torn off the mask to expose a Frost the public never knew: a flawed man with more than his share of personal tragedy, a major poet with more than his share of fear.

Indeed, along with Ezra Pound, T.S. Eliot, and Wallace...