From a fine British author, little known in the US (The Elephant War, 1971, available in paper, is a sequel to Maria Escapes): an entertainingly old-fashioned novel about Victorian Oxford, published in Britain in 1957 as The Warden's Niece. Resourcefully fleeing her dreary boarding school, orphaned Maria, 11, catches a train to amiable but abstracted Uncle Hadden, an Oxford college warden. Though she's met him just once, he's her new guardian; he decides that she'll study with his neighbors' three sons, who have an amusingly idiosyncratic tutor. Maria, who hopes to be a classics professor, is well suited by this and soon engaged in the boys' pranks and pursuits and in endeavoring to prove herself by researching an unidentified boy in a 17th-century drawing. Painfully shy but intrepid, she talks her way into the Bodleian, sidesteps fierce housekeepers, and pieces together a history that finally engages her increasingly affectionate uncle's full attention. The lively dialogue and pungent descriptions here recall Trollope's satirical but kindly perceptions. Avery reanimates a period when education for girls was controversial and a child could be enthusiastic about exploring epitaphs in a country church; creates spirited characters whose unfailing courtesy in no way inhibits their mischief; and provides suspenseful escapades as well as a satisfying historical mystery. It's to be hoped that the sequels will follow Maria to the US. (Fiction. 10- 13)