Between 1909 and 1923, Franz Kafka kept what he called his Tagebücher, or “diaries”. At first glance, much of their content is strikingly unrecognisable as diary entries – often undated, penned deep into the night in dense handwriting, with crossings-out, corrections and insertions, now and then accompanied by drawings.

Across these 12 notebooks and two bundles of loose paper, the German-speaking Jewish Prague native interspersed many different kinds of writing: not just records of daily events, reflections and observations, but also drafts of letters, accounts of dreams, outbursts of anguish and bouts of self-torment, enigmatic aphorisms, and all-but-finished stories.

It’s often difficult to discern whether Kafka is registering a private experience, crafting fiction, or transforming one into the other. Yet, what emerges is an unprecedentedly rich picture of the writer wrestling his literary vision into being – a picture that, until now, has been obscured for anglophone readers.

The sole previous version of Kafka’s Tagebücher in English, first published in the late 1940s, is based on the outdated, bowdlerised German edition prepared by Kafka’s closest friend and literary executor,