Hilary McKay, whose spirited family sagas include The Exiles trilogy and Saffy’s Angel and four subsequent novels about the Casson clan, has written a sequel of a different sort. In Wishing for Tomorrow, due from McElderry Books, she continues the story begun by Frances Hodgson Burnett in her 1905 classic, A Little Princess. McKay discussed her new book by phone from her home in Derbyshire, England.

Do you have strong childhood memories of reading A Little Princess?

Oh, yes. As a child, I read the novel so many times. In fact I read it and reread it until my copy almost fell to pieces. My sister and I knew the novel so well that we could actually recite it. It became almost like theater to us.

What was it about the novel that so captivated you?

Well, it was such another world, wasn’t it? It was enclosed and lovely and such a complete world that one could step into. I loved going into other worlds. And in this one, the colors were so very vivid and the background so real. The novel was so beautifully put together, but I always felt the story was far too short and I always wondered how it could be made a bit longer.

When did you decide you’d like to extend Burnett’s story?

I remember thinking when my daughter was born that A Little Princess was one of the stories I really looked forward to sharing with her. When she got old enough and we were able to enjoy the novel together, it was such a nice chance to come back to it again. And while we were reading it, my daughter asked, “What happened to Ermengarde, the little girl who was left behind when Sara left Miss Minchin’s?” And I realized that was the exact question I wanted to ask!

And to answer?

Yes. Once I started to think about what might have happened to Ermie, Lottie, Lavinia, and the other girls, the idea just took off. I enjoyed answering the question very much.

So the story came easily to you?

Very easily. I think because these characters are such a part of my consciousness. The characters were there and only had to be elaborated on. I had to think quite a bit about why they behaved the way they did in the first story. I could have written much more, I think. It was cutting it down that was the difficult thing.

Was writing about characters created by another author a very different challenge than writing a story involving your own characters?

Not really, actually. I didn’t notice that it was very different, since once you possess the characters yourself, you get to know them very quickly. Once I started hearing their voices, the story took off. It was pure pleasure to write, and to research.

What did your research entail?

Well, I got hold of prospectuses of schools at that time, and I looked over old textbooks and cookery books. I found recipes for the horrible things that children at schools were made to eat then. I don’t know how they survived! I also researched old school uniforms, and looked into what maids were paid at the time and what they were expected to do. And I drew plans of Miss Minchin’s house, and of the London square where the girls took walks.

Given that Burnett wrote A Little Princess more than a century ago, did you consciously add a modern sensibility to your sequel, to tailor it to today’s readers?

Well, the writing really had to be somewhat different, since so much has changed since the time A Little Princess was written 100 years ago. I think children today want to know more about the “why” in situations—why characters are behaving as they are. I did put in a bit of background about certain aspects of the novel and of the characters, without over-analyzing it.

You introduce several new characters in your novel, including Alice, the feisty, outspoken new maid. She’s quite different from Becky, the maid who leaves to live with Sara.

Yes, she is. I knew that there had to be a maid helping out, and I felt I couldn’t have anyone remotely like Becky. Alice is a good link to the outside world, a doorway to the world beyond Miss Minchin’s.

Sara has obviously left the world of Miss Minchin behind in this novel, living in the south of England and eventually preparing to return to India with her guardian. Yet she is very much a presence in this novel, through her letters to Ermie and then with her final visit to London.

Sara had to be there, but not as a physical character. She is a very important part of the book in a very quiet way, since she is so very important to Ermie, who would have been desolate to be left behind and not have Sara in her life somehow.

Are you at peace with where you left all the girls at the end of Wishing for Tomorrow, or will their story have another chapter?

I would like to go on to write another story. I had written an epilogue for this book, about what the girls were doing 10 years later, but we decided not to include it. This ending was better. It was the right one to use. But I think it would be nice to look forward and see what the girls are doing in 10 years. That would bring them up to the beginning of the First World War, which was an interesting period. A lot was changing for girls then.

What are you writing currently?

I’ve actually started a new story about the Cassons.

Wonderful news! But wasn’t Forever Rose meant to be the final installment of that family saga?

Well, I wasn’t going to have another, but on my Web site in the U.K. I have received hundreds of requests from children for more Casson stories. On the Web site, Rose keeps a blog and readers keep downloading it to give to friends as presents. So I decided to do a prequel, about Caddy when she was little.

Your American fans will be happy to hear that that novel is coming. Speaking of fans, what was your daughter’s reaction to Wishing for Tomorrow?

She said she enjoyed it very much, but I don’t think she’d ever say she didn’t like it. But she’s 12 now, and, quite honestly, is a bit more into vampires at the moment!

Wishing for Tomorrow by Hilary McKay. McElderry, $16.99 Jan. 2010 ISBN 978-1-442-40169-3