Edward Thomas’s status in the public mind can be split into two clear eras: pre-Hollis and post-Hollis. As a result of the success of Matthew Hollis’s momentous biography, Now All Roads Lead To France, the shy, tortured poet now has a public profile approaching that of Owen, Brooke and Sassoon. This newfound recognition is reinforced by The Dark Earth and the Light Sky, Nick Dear’s new theatrical take on Thomas’s life.

It is only fitting that Now All Roads Lead To France was on sale in the lobby, as the two works combine to illuminate different sides of Thomas; each one is strong where the other is weak. Now All Roads is very much a poet’s biography: Hollis, an accomplished poet himself, seeks to explain how Thomas, a critic and hack who could write 15 book reviews a week, was able to channel his years of critical engagement with poetry into an extraordinary bout of creativity between December 1914 and his death at the Battle of Arras in April 1917. The Dark Earth and the Light Sky, in contrast, is weakest on the poetry. The play has an unfortunate habit of telling rather than showing: the significance of Thomas’s poetry is largely conveyed through stilted expository conversations between Thomas (Pip Carter) and his mentor Robert Frost (Shaun Dooley). This is a shame as when we finally do hear Thomas’s poetry – a closing rendition of “Lights Out” – it has a raw emotional power.

However, where The Dark Earth and the Light Sky thrives is in its essential humanity. This applies to its portrayal of Thomas himself but even more to its portrayal of his wife Helen (Hattie Morahan). Where the Helen Thomas of Hollis’s biography disappears for large swathes of the book, the Helen Thomas of Dear’s play carries the drama’s emotional weight. While Pip Carter is excellent, capturing Thomas’s awkwardness and even bearing a marked resemblance to the real-life poet, Hattie Morahan is electric as Helen – the independent but devoted wife whose steadfastness to her often unfeeling husband only increases after his death. Indeed, the play is strongest in exploring how Helen deals with the memory of her husband in the ensuing days and years. In a perfect illustration of the play’s symbiotic relationship with Hollis’s biography, the best scene – a ferocious, intense exchange between Frost and Helen over the memoirs she had written – is dealt with in Hollis’s book in less than a paragraph.

Richard Eyre’s production is unassuming but confident: the set, designed by Bob Crowley, consists solely of a ground of bare earth, some chairs, some hay bales and a screen onto which various backdrops are economically projected. The effect of this is to keep the focus on the human drama while also emphasising Thomas’s fervour for the pastoral. Buy the book, but also watch the play: to quote Thomas himself, “beauty is there”.

The Dark Earth and the Light Sky continues at the Almeida Theatre until January 12 2013. More information and tickets can be found on the Almeida website.