This is an extraordinary book about memory and how we construct the past, about climate change and war, about the intricacies of human relationships, and the difficulty of ever understanding what goes on between people. This review contains more spoilers than usual!

The novel starts in 2119 with an academic Tom Metcalfe searching the archives to find out more about a famous poet from a century before, and a lost poem. Everything ever posted on the Internet is available but the world has changed beyond recognition, decimated by war and climate change. The United Kingdom is an archipelago, life expectation has been significantly reduced by nuclear radiation, food is an artificial protein, while civilisation and the humanities (including history as an area of study) are definitely on the slide.

Specifically, Tom is researching a famous poet Francis Blundy and a sonnet sequence written for the birthday of his wife Vivien and recited at her birthday party in 2014. There is evidence about this dinner party in emails, journals, contemporary reports and the recounted memories of those who attended but do they tell the full story?

No, they do not and in the second half of the novel a missing journal written by Vivien is uncovered (both mentally and physically) and it tells another – quite different -story.

The link between all this is memory and the capacity of human beings to reconstruct the past rather than learn from it. Despite the lessons of two global wars, humanity has walked and talked itself into another global conflict and catastrophe. Climate change denial has allowed the weather to transform the planet so that civilisation is barely hanging on despite the obvious signs that all this was coming. Meanwhile, the pursuit of the lost poem has created its own mythology and is yet another total failure – albeit on a smaller scale – to see the obvious. In many ways, this is a very angry book!

Vivien’s journal which takes up the second part of the novel reveals a character which appeared to be unknowable to friends, colleagues and others. Given Ian McEwan’s long-running battles with his ex-wife, Penny Allen, including a ‘gagging’ injunction to stop her, allegedly, from giving her own side of their ‘story’, while he made use of their life together in his novels, is fascinating, given that here an ex-wife is given a hugely significant voice in terms of making sense of the plot. You can make up your own mind whether, in this sense, What We Can Know is a kind of apology to her or simply showing that the novelist can still, without difficulty, appropriate the intimate memories of an ex and do with them as he likes. Francis Blundy gives the clue that it might be the former which is preferable!

It is also important to say that is an excellent story, superbly unfolded, with entertaining characters. It is well worth a read and could make you think twice about what you record in those locked files on the internet!