In Ladies’ Lunch, a new short story by the American writer Lore Segal, five old women gather together to eat and to talk, as they have done every other month for the last 30 years. On their agenda today: How to Prevent the Inevitable. One of them, Lotte, complains loudly about her diet. Doctors, she tells the others, should study the correlation between salt-free food and depression. But if she is tough – her sarcasm belongs to a person half her age – what use, really, is this to her now? Fighting talk is no kind of weapon in the war against children who plan on spiriting you clean out of New York and into a place called Three Trees in the Hudson Valley. The next time the women meet, they’re only four. Together, they fantasise about rescuing Lotte, but of course it’s impossible: how to squeeze in such a mission when they each have so many medical appointments?

In The Journal I Did Not Keep, a rattle bag of writing that comprises a kind of retrospective of Segal’s long career, there are several stories starring Lotte and the others and each one is delightful. Blackly funny and threaded with an indignant bewilderment that is pure gold, they are a sharp and necessary reminder of how rarely one tends to encounter seriously good fiction about old age (we can blame publishing’s dispiriting obsession with youth for this, though perhaps it also has something to do with the fact that by the time a writer is fully qualified to deal with the subject, she may also be too weary to bother). But would I recommend that you go out and buy this book for these tales alone? I must admit that I would not.

I understand why Melville House has put The Journal I Did Not Keep together. Her publisher rightly believes that Segal, who is 91 and still writes for five hours a day, should be vastly better known. In the US, where her first novel, Other People’s Houses (1964), was serialised in the New Yorker, and Shakespeare’s Kitchen (2007) was a finalist for the Pulitzer prize, she tends still to be thought of as a writer’s writer; in the UK, she is hardly read at all. But I’m not convinced that the way to bring her to new readers is by gathering together these extracts from her novels, some new and old stories, some scraps of memoir and a few essays. Whether by accident or design, the result is oddly repetitive, particularly in the sections of the book devoted to nonfiction.

A sharp and necessary reminder of how rarely one tends to encounter seriously good fiction about old age

Much of Segal’s writing springs from what she calls her “ur-story”: as a girl, she arrived in Britain from Nazi-occupied Vienna on the Kindertransport (unlike the parents of many of the children, hers were eventually able to join her in Britain; she and her mother emigrated to the US in 1951). In The Journal I Did Not Keep, we read about this again and again and while all that she experienced never seems anything less than gravely fascinating – even as she is wry about the spinster teachers at her nice English school or the signs on the south coast being switched ahead of any German invasion, her descriptions are backed by the horror of what might have been – I soon began to tire of certain phrases (a problem born of clumping together stories on the same subject that previously appeared at different times, in different places).

I was happier when she drifted away from the matter of memory, focusing her wit, her sagacity and her deft way with dialogue on other subjects altogether. My favourite piece of nonfiction in the book is about the writer John Gardner, who was published by her husband, David, with whom she often used to stay after David died. Her account of Gardner’s family life comes at you like a super-droll, super-literary and super-short version of Rick Moody’s The Ice Storm; the genius of it lies in what she doesn’t say, not what she does.

As this piece and the Lotte stories make clear, Segal is a marvellous and singular writer. But she is ill-served by this baggy, stop-start collection. My advice to new readers: begin elsewhere.

• The Journal I Did Not Keep by Lore Segal is published by Melville House (£25). To order a copy go to guardianbookshop.com or call 0330 333 6846. Free UK p&p over £15, online orders only. Phone orders min p&p of £1.99