In 1890 Anton Chekhov did a most unChekhovian thing: he battled 4000 miles across Russia in order to conduct a survey of the penal colonies on Sakhalin Island. His travel book on the subject, Sakhalin Island, is a masterclass of the genre, and to my mind, not sufficiently widely read.

Before departure, Chekhov said he had ‘wasted his life in fornication’ (who hasn’t?), so he went to Sakhalin to be useful – to report on the various kinds of settlements where exiles rotted in prisons and forced labour camps. His pages conjure broken shafts of springless carriages, a pond of light cast by a tallow candle in a hovel, and the sweet call of a bittern through the darkness on a night ferry. A sausage ‘tastes like a dog’s tail soaked in tar’ and at times the narrator, ‘felt my soul was made of jelly.’

Sailing across the Tatar Strait on the final leg to Sakhalin (an island twice the size of Greece), Chekhov wrote, ‘On my left monstrous fires were burning, above them the mountains, and beyond the mountains a red glow rose to the sky from remote conflagrations. It seemed that all of Sakhalin was on fire.’ He goes on to paint a picture of utter degradation – children sold for a pint of alcohol, prepubescent girls forced into prostitution, men chained to wheelbarrows. ‘It has brought me to realise,’ he wrote, ‘the real meaning of exile – capital punishment has been given a different form.’

Although the journey and the subsequent three-month sojourn on the island were gruelling beyond belief, especially for a man in poor health, there were lights in the darkness. At one point Chekhov reflects, ‘How rich Russia is in good people.’

Few writers reach the same level in fiction and non-fiction (exceptions? Steinbeck, Orwell, Hemingway . . .). Chekhov is up there. Sakhalin Island is both travel and investigative journalism; the style is quite different from that of the short stories, but equally affective, and the book deserves to be read in its own right. But Chekhov felt mighty peculiar about it. He wrote to his surviving brother to say that when he sat down with his pen and travel notebook, he felt he was wearing the wrong trousers.