I CAPTURE THE CASTLE By Dodie Smith (1948)

PICTURE a 600-year-old castle in southern England. Give it a moat. On an ancient mound nearby, put Belmotte Tower, the last remnant of a still older castle.

Now, inside the castle put no furniture at all, except a few pieces from junk shops. I'll explain why in a minute. Provide no electricity, either, even though the year is 1935, and you can see the lights twinkle in the little village a mile away. But do sketch in six human figures: the Mortmain family and their one solitary retainer.

The Mortmains of Godsend Castle are an interesting group. The father is a handsome man in his forties. Once a distinguished writer, he is now a semi-recluse who spends nearly all his time holed up in the gate tower. He reads detective stories and does crosswords. The mother -- but there is no mother. Instead there's a stepmother, a 29-year-old ex-model named Topaz who has long pale hair to her waist and ambitions to be an intellectual.

Then there are three children, plus the retainer. I'll take them in ascending order of importance. Thomas, the only son, is a boy of 15. He is bright and nice -- and he plays a very minor role in the action. Then comes Stephen Colly, the retainer. People in 1990 tend automatically to put the adjective "aged" in front of retainer, but actually they came in all ages. Stephen is no bent figure shuffling in with the tea; he's a good-looking boy of 18. His mother used to be the family maid -- and when she died, leaving no visible relatives, it just seemed natural for him to stay on at the castle. He plays a major role, especially late in the book when he is "discovered" by a rich woman in London.

Next comes Rose, the elder daughter. She is beautiful, intensely practical, mad about clothes and 20 years old. She is co-heroine of the book. By American standards of 1990, she's a bit unusual, because she's never had a boyfriend. This is not because she isn't dying to, though, but because they are so isolated in the castle. And this is England, of course. It would have to be someone of her own class.

Finally, there's Cassandra Mortmain, age 17. By any standards, Cassandra is an unusual girl. She's twice as imaginative and three times as alive as most human beings. Even Rose's hunger for experience, adventure, men, etc. etc., is feeble compared to Cassandra's. She is not only co-heroine, she narrates the book, and that is one of its greatest charms. Cassandra's mode of narration is (1) romantic, (2) funny, (3) full of insight and (4) what any teenage girl would be proud to come up with, if she happened to be a brilliant writer. By this I mean that Cassandra sounds authentic -- and authentically 17. There is no hint of Dodie Smith, the adult author, manipulating her behind the scenes. It is truly Cassandra's book.

But enough. You have been waiting impatiently to learn why these people live almost without furniture. It's for the same reason that clothes-loving Rose has about three dresses, and that the whole family (plus Stephen) are perpetually hungry. They have run out of money.

They can't sell the castle, because they don't own it. Back when the father was getting huge royalties -- especially from America, where his book Jacob Wrestling was a bestseller -- he rented the castle on a 40-year lease. At the moment he hasn't paid the rent in three years -- and piece by piece they have sold all the furniture. Remember that 1935 was the depth of the Great Depression, and it was not unusual to have run out of money.

As the book opens, it's twilight of an April day. Rose is in the kitchen, ironing her only nightgown. Stephen Colly is pumping up water from the cistern in the castle courtyard. Thomas is still at school. Mr. Mortmain is holed up in the gate tower. Topaz is bending over the kitchen fire, blowing; the weather is rainy and the castle is very cold. As for Cassandra, she is sitting in the kitchen sink, recording the scene in her diary.

The sink? Why there? Because not only does the castle lack electricity, the Mortmains can't afford many candles, and the sink's in front of the only window where there's enough light left to write by. Anyway, Cassandra likes to put things picturesquely. As she soon admits, it's really only her feet that are in the sink. "The rest of me is on the draining board, which I have padded with our dog's blanket and the tea-cosy." A NUMBER of things soon happen. Stephen Colly, having finished pumping the water, comes in and shyly hands Cassandra yet another of the poems he keeps copying out of anthologies and giving to her. Thomas, home from school, checks the henhouse and finds the hens have resumed laying, which means they'll get an egg each for dinner, instead of just bread and margarine. Rose and Topaz have a sharp quarrel over money. Rose wants Topaz to go back to London and resume posing for artists. Topaz doesn't want to be away from her husband. Besides, she says, the artist who pays her best clearly thinks of her as a sex object. "I've had more trouble with him than I should care to let your father know."

"Rose said, 'I should have thought it was worth while to have a little trouble in order to earn some real money.'

" 'Then you have the trouble, dear,' said Topaz."

This infuriates Rose, who's longing to have that kind of trouble, and sees no prospects. She flings her head back dramatically and says, "It may interest you to know that for some time now, I've been considering selling myself. If necessary, I shall go on the streets."

Cassandra, from the sink, points out that this will be hard to do in rural Suffolk. Rose sees that.

"But if Topaz will kindly lend me the fare to London and give me a few hints -- "

Rose doesn't, of course, sell herself in London. Instead, Stephen gets a job, at 25 shillings a week, on a nearby farm. And soon after that the Americans come. The Americans are two brothers, Simon and Neil Cotton, who one dark evening blunder up the muddy track that leads to the castle. Both are husband material. All sorts of adventures follow.

I Capture the Castle is a hard book to classify. It is much too funny to be merely a teen romance, or merely any kind of romance. It's much too seriously romantic to be a spoof, a burlesque, or the kind of book they call "rollicking." In fact, it's much too individual and much too well-written to be labeled at all.

Except maybe with one label that says, "Contents: 100 percent Pure Delight." And another that says, "Warning: This style may prove addictive."

That's a real danger. Because if you, as a teenage girl or man of 53, read I Capture the Castle, and fall in love with it, you will naturally want to go on to more. There is no more. Dodie Smith wrote numerous other books, including the one the Disney factory adapted for 101 Dalmatians, and some are better than others. But I Capture the Castle is her only masterpiece. I don't say that derogatively. After all, how many writers have produced even one?

Noel Perrin teaches American literature at Dartmouth.

Note on availability: "I Capture the Castle" is available in two English editions: a Heinemann hardcover at

9.95 and a Bodley Head paperback for

4.95. But, as always, remember to try the library and second-hand bookstores.