The Dark Earth and the Light Sky, Almeida Theatre, London The beautiful poetry of Edward Thomas - ostensibly pastoral but often leading us to the mysterious, unsettling edges of consciousness - came in a late spurt of creativity. He wrote his first poem in 1914, at the age of 36, after years of influential reviewing and assorted literary hackwork. In April 1917, he was killed at the battle of Arras when the vacuum left by a passing German shell literally sucked the life out of his body. The fact that he eventually found his vocation has been attributed to the encouragement of the American poet, Robert Frost, with whom he struck up a close friendship in 1913. A married family man old enough to avoid the call-up, Thomas not only volunteered but insisted on going to the front line. In Nick Dear's sensitive, insightful new play, there's a striking moment where we see the poet cradling a crying baby in one arm while his free hand toys with a revolver. The War makes him realise that the English countryside is "not genuinely mine unless I am prepared to protect it." But did it also give this complex figure, dogged by self-doubt and depression, the opportunity to fulfil a deep pre-existing death wish? The form of Dear's play - in which the enigmatic protagonist is viewed from the discrepant perspectives of those closest to him - powerfully pinpoints the paradox that Thomas was a man who inspired the love of which he was himself incapable. Pip Carter superbly conveys his haunted near-solipsism and the almost comically brusque and inactive detachment with which registers his untoward effects on his sorely tried wife Helen (a damaged free-spirit in Hattie Morahan's immensely moving performance). Richard Eyre's spare, exquisitely modulated production is performed on an earth-covered stage, the different landscapes and atmospheres suggested by the wash of Peter Mumford's subtle, lovely lighting against the brick-wall backdrop. It also negotiates with eloquent fluidity the play's tricky time-scheme with its sudden leaps forward to show us the poet's contested emotional and poetic legacy. As Frost, Shaun Dooley exudes a muscular American confidence in poetry as a career as well as a calling, while Pandora Colin snags the heart as Eleanor Farjeon, Thomas's devoted, permanently virginal supporter. Perhaps limitingly, for a play where its nature is often discussed, we get to hear only tiny snatches of the poetry until Carter's searching delivery of "Lights Out" brings this clear-eyed compassionate drama to a quietly shattering climax.