Epistolary novels were once all the rage, from the epic Clarissa to the lurid fun of Dracula. They don’t come along very often now, perhaps because they can be tricky to do well: all those gaps and omissions, the need for a flawless command of tone and voice, the problem of creating movement within an unusually hermetic form. But every now and then a book appears that’s a breakout success. The 2000s saw two epistolary smash hits in We Need to Talk about Kevin and The Guernsey Literary and Potato Peel Pie Society (boy, are those different reading experiences), while in the 2010s there was Where’d You Go, Bernadette?

Now we have Virginia Evans’s The Correspondent. It’s been one of those word-of-mouth sensations that puts a spring back into publishers’ steps, a bestseller on both sides of the Atlantic, now shortlisted for the Women’s prize for fiction. It’s easy to see why, given that it’s such an immensely enjoyable read.

Three times a week, 73-year-old Sybil Van Antwerp sits down at her desk in her Maryland home to write her letters. Her correspondence has been, as she puts it, “the mainstay of my life”. Recipients include her best friend Rosalie, her brother Felix, the unhappy young son of a former colleague, and an unnamed correspondent to whom Sybil writes much more emotionally raw letters, which remain unsent and fulfil a similar function to the diary sections often included in older epistolary novels.

Sybil’s voice is direct, irascible, always somewhat at odds with the world around her: “Dear Rosalie,” begins one letter briskly, “I haven’t heard from you. Waiting for your response to my last, but cannot wait for ever.” She is a pleasingly contradictory character: prickly and obstinate, but equally capable of generosity and wisdom.

Crucially, the novel never feels static, despite its form. Covering a span of several years, the narrative packs in the emergence of two separate suitors for Sybil, glimpses of her formidable legal career, a DNA testing kit, and the painful backstory of the death of her son, Gilbert, as a child. Another source of tension is the fact that Sybil is losing her sight, and the correspondence that has formed her “manner of living” will soon be brought to an end.

Replies are included from time to time, which provides variety and texture. Felix is a particular joy, matching Sybil in directness but with added offhand charm (“You better not say those kinds of things about her marriage to your daughter with things already strained,” he counsels Sybil – “ your own marriage was a filthy sewer”).

Evans also has Sybil write to real-life figures, including Ann Patchett, George Lucas and Joan Didion. A couple of fictionalised replies from Didion are included, as well as her implicit responses embedded within Sybil’s own letters, and I felt some discomfort with this brief act of ventriloquism, given the subject is the loss of a child. Perhaps Evans’s decision is justified by the fact that the real Didion wrote in some depth about her daughter’s death, but, still, those words were Didion’s own.

But, as a character study, the book is skilful and moving. Evans is especially sharp on the role correspondence has played in Sybil’s life. Late on, Sybil reflects: “When I was younger, by writing letters I found a framework that made living easier, and that has never changed. However, I do wonder if by conducting the most intimate relationships of my life in correspondence, I have kept, since I was a child, a distance between myself and others.” The reader feels how accurately this applies to Sybil, and we can see the distance created within the syntax itself. It’s satisfying to find form, character and style interwoven in this way.

The book is also, of course, a paean to the art of correspondence. By the time I finished it, I found myself composing letters in my head to all my friends and acquaintances, God help them. Long live the epistolary renaissance.