GOOD NEWS FOR WOULD-BE WRITERS! You too can create a costume romance about the British aristocracy, a profitable novel selected by book clubs, auctioned off to competing paperback publishers and optioned by film producers. No matter where you're from, you can do it, because you already know enough about the tribal customs of great country houses in the British Isles before the first World War. That is to say, anybody who has put in a lot of television watching time on Upstairs, Downstairs and The Duchess of Duke Street and all the rest of those imports, is ready to go. Just scramble them together and out will pop your novel. Of course you must try to think up a plot as brisk as Richard Peck's, in which two brunette beauties -- an innocent lady's maid and her nasty mistress -- are miraculously identical. Oh, what confusion in dark hallways when the brutish chauffeur lays his rough hands on the wrong girl! Oh, what excitement when maid and mistress sail for America in 1912 on a certain "unsinkable" liner of the White Star line (just like Lady Margery, remember?)!

If you can correctly fill in the blanks in these selections from Amanda/Miranda, you're off to a flying start. 1. "When Sir Timothy and her ladyship acquired this property, I fear they little reckoned on the ---- they fell heir to."

a. gigantic rotten roof

b. miles of backed-up drains

c. legacy of depravity 2. "In my world of lavender silks he is more the rough beast, chained but ---- that is answered by the animal within me."

a. howling to the moon with the wild bark

b. barking to the stars with the desparing howl

c. raging with the lust 3. "His chin was ---- above the high white collar I had seen him wear only once before, at the Ventnor ball."

a. bleeding

b. flabby

c. square and resolute 4. "There was the first sound, as the seam of Mary's ---- tore from neck to shoulder."

a. bathrobe

b. pajama top

c. nightdress 5. "The howling, rainswept night when I had first gone to ----, urged along by Mr. Finley, was far from my mind that day."

a. the supermarket

b. Grandma's house

c. Smuggler's Cottage 6. "She had moments of a special brilliance, noments when her ---- face burned brighter from some dark inner flame."

a. pub-nosed, freckled

b. chubby, pink-cheeked

c. violet-eyed, porcelain-complexioned 7. "It was clear enough that the ---- had struck again."

a. dockworkers

b. third baseman

c. madman 8. "I was not, after all, likely to be proof against the force of his ---- much longer."

a. ferocious backhand

b. savage forehand

c. animal passion 9. "Loosed from its tight knot, her black hair ----."

a. straggled in greasy strings

b. stuck out from her head in all directions

c. hung down to tumble around her shoulders 10. "The great ship rose above us . . . and on the bow her name was lettered in gold: ----."

a. Jersey City

b. Rotterdam

c. Titanic

If you filled in all the blanks with the letter "c" you were right every time. The ease of these silly choices is what is the matter with a book like this. Missing is that valuable quality, authenticity, with its small surprises -- "Oh, is that the way it was? I didn't know that" -- and its little shocks of recognition -- "Yes, that's true; now that I see it in print, I remember it."

Richard Peck could probably write a good novel about his birthplace in Illinois, or about army bases in Germany, or even about the university in England where he was a student for a while. But his Whitwell Hall, with its columned portico, its balustraded terraces, its marble floors, paneled walls, canopied beds, Grecian temple and circular drive, is a confectionary stereotype, a palace made of sugar.

Authenticity creeps into the book only once, in a skillful description of the sinking of the Titanic. One suspects that the author was writing at last from experience, the eyewitness accounts of survivors. It is a welcome relief in this jumbled hand-me-down from Mishmashterpiece Theatre.