Collections of poetry, when people wish gently to disparage them, are called "slim vols". This is not a slim vol. It is a fat vol. More than 1,000 pages, and well over 1,000 poems. Or, to put it another way: there are 40 pages of contents alone.

So: Elizabeth Jennings wrote a lot; and here what she has written is supplemented by 130 pages of previously unpublished poetry: undated, or juvenilia, or whatnot. Well, in for a penny, eh?

The point, though, is not to mistake being prolific with being prolix. It's fairly safe to say that what was hitherto unpublished neither represents the dregs of her work, nor sticks out as something unrepresentative altogether. "A Briefness", itself a briefness of a poem, ends with the lines: " I remember reflecting / 'Women who don't believe in God / Don't bother to look elegant,'" which is of course a highly debatable proposition on the face of it, but rather funny, and we should remember the quote from TS Eliot she makes use of a few pages before: "if we learn to read poetry properly, the poet never persuades us to believe anything ... What we learn from Dante, and the Bhagavad Gita, or any other religious poetry is what it feels like to believe that religion."

Jennings was, famously, Catholic; despite a bruising encounter with a horrible priest at confession which "festered" within her for years, and did very little to help, and probably much to make worse, her problems with sex (Emma Mason contributes a long and very illuminating afterword to this edition, which examines this question without going into prurient detail). Later on she got luckier with a much more sympathetic priest; but anyway her religion never got in the way of her affection and respect for atheist Larkin. (From "For Philip Larkin": "The last thing you would have wanted  / A poem in praise of you.")

Jennings was also famously batty-looking, with a personal style that, as she got older, got closer to that of the bag lady; she wore plimsolls when collecting her CBE. (Good for her, you might say.) She was also modest and slightly out of the loop (although she was an undergraduate at Oxford and lived there all her life, she was not an academic), and was always tacked on towards the end of the factitious list of "Movement" poets of the 1950s  Larkin, Donald Davie and so on.

She was popular, too, her selected and collected poems of 1979 and 1986 selling between them 86,000 copies; and you can see why. The work is accessible without being shallow. Here's the second half of "London", describing her disappointment when taken to the capital as a child: "Oh, Piccadilly Circus / Was just a roundabout, / No monkeys there, no horses, / No tigers leaping out. / You see, I thought a circus / Was always just the same. / I never guessed that it could be / A lying, cheating NAME." You might think that there is something too rumpty-tumpty about this, but the savage snap of the final line suggests far better the painful puncturing of illusions than if it had been preceded by something more complex  while also suggesting that there is something childish about the observation itself.

This is the kind of verse that makes us think of Wendy Cope (of whom, by the way, I think very highly), but Jennings had many registers, as well as modes: yet she most often returns to rhymed form, whether abab quatrains or sonnets, of which there are legion. Musing on what JMW Turner's "bonds and limits" were, she says there must have been some "since art can only flourish locked and barred / By form". (I'd like to have quoted the whole sonnet, because it is imperishably useful not just about art in general, but about Turner in particular, and should be displayed at the beginning, or the end, of every proper exhibition of his work.) But there is no sterility here: I defy you to read "A Living Death" and not be on the verge of tears by the end of it ("I am caught up / Within a death that does not die ") This is a supremely dippable-into book. Its bulk is liberating, not intimidating.