The world can be divided into two unequal groups: those who, when they hear the name Day-Lewis, think of Daniel, the Oscar-winning star of “My Left Foot” and “Gangs of New York”; and the much smaller number for whom the name evokes the actor’s father, Cecil, who was England’s poet laureate from 1967 until his death in 1972. Of course, it is not surprising that a movie actor should be more famous than a poet. Cecil Day-Lewis himself, though he wrote and advocated an accessible, socially engaged style of poetry, knew that poems could never have the reach of films. “To many people,” he once wrote, the poet “looks like a man desperately and unintelligibly semaphoring from a sandcastle crumbling at the tide’s encroachment.”

No, the strange thing about C. Day-Lewis, as he always signed himself, is that while only a small fraction of the public knows his name, even that fraction probably couldn’t name three of his poems. It’s not that Day-Lewis had an obscure life or a thwarted career. For four decades, he was one of England’s most prominent writers — not just a poet, but the author of a series of best-selling thrillers, published under the name Nicholas Blake; a popular speaker and reader of verse; a radio and television broadcaster; and a reliable presence on judging committees and arts panels. If there was a set of endowed lectures in the English-speaking world, Day-Lewis gave them: He was Professor of Poetry at Oxford, Norton lecturer at Harvard, and Clark lecturer at Cambridge.

But even as his fame grew, his literary reputation stagnated. Today, he has the most ungrateful kind of posterity: He is remembered not for his own sake but as the representative of a school, and his name is seldom mentioned except at the end of a list. The name at the top of that list is always W.H. Auden, who in the early 1930s swam into view as a new planet in the galaxy of English poetry. Circling in his mighty orbit were the socially radical, ardently contemporary poets who came to be known as the Pylon poets or the Thirties poets: Louis Macneice, Stephen Spender, and Day-Lewis. Macneice managed to break free and establish his own center of gravity. But to this day, Spender and Day-Lewis are still Auden’s moons; and while they both wrote copiously throughout their lives, it is their early, Audenesque poems that are most often anthologized. You can hear the influence clearly in Day-Lewis’s “The Magnetic Mountain,” the title poem of his reputation-making 1933 collection:

Somewhere beyond the railheads
Of reason, south or north,
Lies a magnetic mountain
Riveting sky to earth.

No line is laid so far.
Ties rusting in a stack
And sleepers — dead men’s bones —
Mark a defeated track …

Near that magnetic mountain
Compass and clock must fail,
For space stands on its head there
And time chases its tail.

This particular blend of industrial imagery, ballad-like rhythm, and enigmatic utopian desire was trademarked by the early Auden. But as Peter Stanford shows in his new biography “C. Day-Lewis: A Life” (Continuum, 368 pages, $32.95), Day-Lewis was present at its creation. The two poets met at Oxford in 1926, when Day-Lewis was a junior and Auden a freshman, and instantly developed a close, rivalrous friendship. Mr. Stanford quotes an anecdote of Day-Lewis’s that gives the flavor of those early days:

Walking the moors one day, we approached one of those dark walls which wind over the contours like strips of liquorice. A hundred yards from the wall, as if on a common impulse, we both began to walk faster; at fifty or sixty yards, we broke into a trot, and we were sprinting all out over the last thirty yards or so. Arriving simultaneously at the wall, we gave each other an amused but also sheepish look.

The friends tied that day, but even then Day-Lewis recognized that, when it came to poetry, Auden was in the lead. “I willingly became his disciple where poetry was concerned,” Day-Lewis said, and the results were obvious in the evolution of his style. While still an undergraduate, he had privately published his first collection, whose title, “Beechen Vigil,” advertised its genteel, pastoral style: “Our mood / is crystal, bright as primrose laughter / rippling beneath the bracken.” The change from primroses to railheads, from Georgian escapism to Thirties engagement, was catalyzed by Auden. Soon after they met, Day-Lewis began to submit his verse to the younger poet for criticism — although, as Mr. Stanford notes, he did not slavishly accept his suggestions.

In fact, as their subsequent work would show, Day-Lewis’s true inspiration was quite different from Auden’s. One of the best things about Mr. Stanford’s biography — a comprehensive, diligent book, sincere but not excessive in its appreciation for its subject — is that he quotes a great deal of Day-Lewis’s verse. This allows the reader who knows the name but not the poetry to see how Day-Lewis developed over time — or, rather, how he circled back to his original, Georgian inspiration. This poetic itinerary, which saw Thomas Hardy displace Auden as Day-Lewis’s tutelary genius, paralleled his political evolution.

In the 1930s, like almost every English writer of his generation, Day-Lewis dallied with communism, joining the Party as a gesture of solidarity with the working class and Republican Spain. But as Mr. Stanford shows, he never quite took the whole thing seriously. The Cheltenham Communist Party cell, he wrote, gave an “impression more of a combined study-group and nonconformist chapel than of a revolutionary body.” While Spender broke dramatically with the Party, contributing to the famous manifesto “The God That Failed,” Day-Lewis simply stopped returning the comrades’ phone calls. By the time World War II began, he was more than ready to return to the patriotic fold, writing such piously hopeful poems as “Watching Post”:

The farmer and I talk for a while of invaders:
But soon we turn to crops — the annual hope,
Making of cider, prizes for ewes. Tonight
How many hearts along this war-mazed valley
Dream of a day when at peace they may work and watch
The small sufficient wonders of the countryside.

The most dramatic section of Mr. Stanford’s biography concerns the war years, but not for political reasons. Day-Lewis, who lost his mother as a child, got married young to his first sweetheart, Mary, and fathered two sons with her. But in the chaotic, carpe diem atmosphere of wartime London, he fell passionately in love with the much more glamorous Rosamond Lehmann, a successful novelist. Throughout the war, Day-Lewis and Lehmann lived in London as an established couple, while Mary raised the children in the country. Finally, when the pressure of this divided life became too great, Day-Lewis confounded Mary and Rosamond by leaving them both for a much younger woman, the actress Jill Balcon. She became Day-Lewis’s second wife, and the mother of his second pair of children, including Daniel. (There was also another child, possibly two, fathered out of wedlock.)

All these events appear, sometimes pretty explicitly, in Day-Lewis’s poetry of the 1940s and 1950s. But even here, there is little violence of feeling or language. Instead, Day-Lewis finds his way to a mild, melancholy resignation, as in “Ending”:

That it should end so! —
Not with mingling tears
Nor one long backward look of woe
Towards a sinking trust,
A heyday’s afterglow;
Not even in the lash and lightning
Cautery of rage!

There is little in this poem that marks it as a product of the 1940s rather than the 1840s. Day-Lewis’s poetry demonstrates the danger that lies in wait for a poet who admires traditional forms and genres: Instead of writing in a tradition, he may find that the tradition is writing him. Day-Lewis was right and noble to argue that poetry should not be a hermetic game, but rather “convey the elemental states of mind a man shares with all other living men and has in common with his remotest ancestors.” But it takes a powerful, even shocking originality to recover those elemental states, which we usually find crusted over with the dead formulas of the past. The absence of that shock is why Day-Lewis remains a part of literary history, rather than a living presence in literature.

akirsch@nysun.com