Impermanence and identity are at the heart of Javier Marías’ latest work, a literary spy tale in which Oxford undergraduate Tomás is recruited into the British secret service after event in the town leave him no choice. Back in Madrid, he marries long-time girlfriend Berta but quickly becomes a stranger to her. Following in the footsteps of his Your Face Tomorrow trilogy, Berta Isla uses the spy genre to explore the human condition: to what extent are we our actions? Does our identity belong to us or to others? And should we fear the passive life, as outcasts from the universe, as he puts it, not ‘shaping the world’?

Tomás is suitably charming; capable, but easily so, he’s a joy to accompany in early chapters before the focus shifts to Berta. She is wilful and thorough, and her research into military intelligence becomes our spy story in place of Tomas’s escapades, kept secret from us as well as from Berta. Marías weaves history and politics with Shakespeare and refrains of T.S. Eliot, which come and go like errant thoughts but linger long after.

This is the closest prose comes to poetry. We need literature like this, however, what stops me from calling Berta Isla a masterpiece is Marías’ tendency to digress, with lines of dialogue separated by pages of theorising that break momentum and put distance between the reader and the characters; the characters themselves read like Marías rather than individuals in their own right. The keen gaze that made me fall in love with Marías is less incisive here because it is less concise. As a novel it is excellent, but as a story it struggles beneath the weight of the author.

Paul Goodman works as a bookseller at Readings Hawthorn.