An equilateral triangle

Robert Frost (1874–1963) and Edward Thomas (1878–1917) are the Pound and Eliot of regular verse, twentieth-century poets who, by tearing off the fustian and listening to how people actually speak, showed how “making it new” need have nothing to do with modernism. And while Frost is much the better known, few rival Thomas as a poets’ poet—the many who have paid tribute to his work include W. H. Auden, Philip Larkin, Ted Hughes, Seamus Heaney, and Derek Walcott.

The story of the Frost–Thomas friendship has its biographical attractions too. When they first met in October 1913, Thomas was thirty-five, Frost thirty-nine. Their lives looked like examples of failed promise. Since coming to England the previous year, Frost had finally published his first book of verse, but it had caused little stir. Thomas might have been an established name on the London...