I wasn’t even conscious of turning the pages. I lived in the story. I laughed at Katy’s scrapes and gasped when she disobeyed her aunt and tried out the broken swing. I felt desperately sorry for her when she hurt her back so badly and became an invalid. I was moved by her kind Cousin Helen and her gentle advice and I hoped against hope that Katy might one day walk again.

I relished the children’s conversations in the marshy thicket they called Paradise, where they made plans for the future and Katy read aloud her little brother Dorry’s hilarious diary, a classic comic piece in itself. (I am frequently tempted to copy him and write ‘Forgit what did’ when I can’t think what to write in my own diary.)

My favourite passage was the Christmas scene in the tenth chapter. Meg, Jo, Beth and Amy, the March sisters in Little Women, had to be content with a bible each, but Katy uses her Christmas money to buy her little sister Elsie a writing desk with ‘a blue velvet lining, and an inkstand with a silver top . . . some little sheets of paper and envelopes, and a pen-handle; the prettiest you can find. Oh! And there must be a lock and key’.

That description has haunted me all my life, and though I now have a splendid writing desk myself, I don’t think it quite matches up to Elsie’s. What Katy Did has haunted me too, and whenever I mention the title to any book-loving woman of a certain age their face lights up. I’m not sure many modern children know Katy, though it’s still a paperback classic. My copy has a girl in a pink checked pinafore and black boots on the cover. Pinafores and boots are obviously Victorian clothing but the child looks modern, if a little quaint. It’s interesting looking back at the many different versions of What Katy Did to see how the artists often reflect her as a contemporary child.

The first edition, published by Roberts Brothers in Boston, had a very different cover: five katydids (a type of grasshopper) are marching along in a line in a rather menacing way, on a sludge-coloured background. A variant cover is poison-ivy green with a clump of bulrushes and two katydids startlingly embellished in gold, waving their feelers. If I’d been a Victorian child, nothing on earth would have made me pick up such a volume. You’d never think that inside those dire covers are a living, breathing family that any child could identify with, even now.

What Katy Did is a classic because of the superbly realistically drawn children and the psychological depth of their depiction, but the plot itself is less original. Victorian children’s books about naughty children having some kind of dreadful accident are two a penny. However, Susan Coolidge is never mawkish and avoids any tragic deathbed scenes. There are occasional didactic passages, especially when Katy’s father tries to make her see the error of her ways. Katy earnestly vows to be more thoughtful, but the author says ‘I am sorry to say that my poor, thoughtless Katy did forget, and did get into another scrape, and that no later than the very next Monday’. Of course the reader immediately longs to know what she does next, and reads on eagerly.

Susan Coolidge apparently wrote What Katy Did at the request of her publisher. It’s such a heartfelt, accomplished book that it’s surprising to think it was written to order. She’d published one children’s book previously, called A New Year’s Bargain, in 1871, a collection of twelve short stories for every month of the year, a book now long forgotten.

Susan Coolidge was a pen name. She was really called Sarah Chauncey Woolsey, and was born in Cleveland, Ohio, in 1845. She was brought up in New Haven, Connecticut, and volunteered as a nurse during the American Civil War – like Louisa M. Alcott.

The Senior Editor at Roberts Brothers had published Louisa M. Alcott’s Little Women in 1868.