In March 2005, Oxford University held a conference about Edward Thomas. There were academic speakers, but also 16 poets, who read poems they had written in honour of Thomas or in which they found themselves to have been influenced by him. "Thomas steals up on you," observed John Fuller, and U A Fanthorpe said: "He comes naturally, I think, to writers in English, like grass growing."
One might picture the history of English poetry as a cocktail party. There's Keats, on a sofa, circled by admirers, there's Dylan Thomas by the bar and Milton by the window, all raising their voices and competing to be heard. Yet there is another way to imagine literary history. Now the poets are a chorus, a school of shared voices; there is still competition, but all join in one project of sound and tone. Thomas is a poet of this second understanding. His voice is a quietly powerful presence just beneath the surface of much modern English poetry.
As Thomas is a poet loved by poets, Matthew Hollis is his perfect biographer. Hollis is the author of the poetry collection Ground Water as well as the editor of an elegant new selection of Thomas's poems, which includes extracts from his published prose and unpublished diaries. These were the rough materials from which Thomas crafted his lines, and here, as in the biography, Hollis gives a portrait of the artist as a man at work: shaping, revising, making poems. The biography, Now All Roads Lead to France, is not a story of the whole life from cradle to grave, but of an important period - the last four years of his life, during which he developed a close friendship with Robert Frost, decided to enlist in the army and fight in the First World War, and turned himself into a poet.
The narrative begins in January 1913, at the opening of the Poetry Bookshop off Theobald's Road in Bloomsbury, London. It was a tense time. "Suffragettes were taking up direct action, breaking shop windows, starting letter-box fires," Hollis writes. "The agricultural labour force was demoralised and impoverished, and England's 'green and pleasant lands' were rarely seen by the industrial classes locked into long and dangerous hours in the factories." These were, as he describes them, "uncertain hours for a fading empire, watching nervously the growing danger of Germany's own imperial aims". At the bookshop opening were many poets, among them Frost, the not-yet-famous chronicler of archetypal American scenes, who had moved to England on the toss of a coin ("Heads England, tails Vancouver").
Thomas was there, too, then 34, unhappily married with three children, and a prolific hack. He had already written more than 20 books:
biographies on commission, criticism and ruminative accounts of countryside walks. He had written too much, and too fast - much of his prose is turgid, forgettable. He was depressive, tall and beautiful.
Over the next two years Thomas and Frost walked together, and talked, and it was Frost who told Thomas to become a poet, specifically by returning to work he had already written and editing those same descriptions into verse. "Adlestrop", which is probably his best-known poem - it was first published in this magazine three weeks after his death in 1917 - grew out of a simple entry in Thomas's diary. It begins:
Yes. I remember Adlestrop -
The name, because one afternoon
Of heat the express-train drew up there
Unwontedly. It was late June.
The poem builds from particular description to a vision of England, and Englishness. Here, as in many of his poems, the essence is discovered through the physical, the abstract through the concrete, and the verse follows the cadences of everyday talk; that opening "Yes" indicates that this is spoken, part of an ongoing conversation. It is a precise casualness.
These are not fireworks but poems, beautifully made and human, compacted down by force of thought and feeling, by craft condensed from common speech. They are marked by certain habits: strategic repetition, so that a simple word gains great weight, and disciplined observation of the natural world. "The Manor Farm", for instance, opens: "The rock-like mud unfroze a little and rills/Ran and sparkled down each side of the road". Elsewhere, an owl's night-time cry is "shaken out long and clear upon the hill". These do not show off but they are splendid.
Thomas wrote 140 poems between December 1914 and December 1916. This is a miraculous achievement, a golden moment of creation - like those of Keats, and Sylvia Plath, and Thomas's contemporary Wilfred Owen - and these are the complete contents of his collected poems. Given the time of writing, the First World War is always at the edges, ominous. In "In Memoriam (Easter, 1915)" the conflict hovers, but is not mentioned:
The flowers left thick at nightfall
in the wood
This Eastertide call into mind the men,
Now far from home, who, with their
Have gathered them and will do never again.
The landscape becomes a kind of witness to the war: its continuities, its seasons and flowers, mark the break.
He did not have to go to war. Thomas was a father, a husband and in his late thirties by the time fighting began. But his love for the land translated itself into a kind of literal patriotism. Now All Roads Lead to France sets out the tragic, inevitable steps.
He enlisted in the Artists Rifles, where he was an instructor, but they were not going to the front, so he joined the Royal Artillery. At training camp in Essex, he wrote poems among the maths calculations he was making to determine the trajectory of shells, and he wrote a poem addressed to each member of his family. He finished arranging his first book in November 1916, and was sent to France the following January. He lived long enough to see the Times Literary Supplement describe him as "a real poet, with the truth in him". Three days later, in Arras, he was killed by concussion from a shell passing close by.
He was watching, until the end, making notes for future poems. In his volume of selected verse, Hollis prints a few entries from Thomas's diary from France, and here we see him still noting nature, perhaps thinking of future poems. "Does a mole ever get hit by a shell?" he asked himself on 25 February 1917. For Thomas, war was not the opposite of nature. A few days before he was killed he noted: "Machine-gun bullets snaking along - hissing like little wormy serpents." Wildlife and the war were all bound up in his way of seeing, in his making of the world.
Daniel Swift is the author of "Bomber County" (Hamish Hamilton, £9.99)