Many in the field of children's literature agree that the criteria making a book appropriate for a particular age group are fuzzy at best and, at worst, wrong.
Jo Carr, a professor of children's literature at the University of Virginia, describes it with this story: As a former librarian for the Fairfax County, Va., system, she says, she frequently listened to patrons' requests for good stories, pulled ''a couple of things off the shelf, and then ran upstairs to the children's room and came back with an armload.''
It's a system she recommends for others. ''If you like fine writing, a good story, and you don't want to feel that the world is going down the drain in a hurry, try children's literature,'' Professor Carr advises.
Asked for a sampling, she came up with this list:
* ''Founding Mothers,'' by Linda Grant DePauw (Houghton Mifflin, 1975). An entertaining history of the women behind the American Revolution.
* ''Tulku,'' by Peter Dickson (Dutton, 1979). A novel about a ''crazy older woman'' who travels around the world and has a tender relationship with a young boy.
* ''A Place Apart,'' by Paula Fox (Farrar, 1980). A novel about a girl who moves to a small town with her widowed mother and becomes involved with an older boy who, she slowly realizes, is a master manipulator.
* ''Autumn Street,'' by Lois Lowry (Houghton, 1980). The story of a young girl living with her disapproving grandmother and loving, distant grandfather while her father fights in World War II. She becomes friends with the cook's son and learns about cultural differences and the awful hatreds - and loves - they sometimes generate.
* ''Cathedral,'' by David McCauley (Houghton, 1973). With fine drawings and clear prose, Mr. McCauley shows how a typical Gothic cathedral was built, stone by stone.
* ''Bridge to Terabithia,'' by Katherine Paterson (Harper, 1977). A beautifully written book about the friendship between two children and their own special magical world.
* ''The Gift Outright: America and Her Poets,'' by Helen Plotz, ed. (Greenwillow, 1977). An outstanding collector of poems, Ms. Plotz has included both admirers and detractrors in this group.
* ''Unleaving,'' by Jill Paton Walsh (Farrar, 1976). A young girl in Britain is persuaded to rent a house she inherits to a reading group from Oxford. She hangs on the fringes of their intellectual discussions, and learns graphically the difference between the emotions and the intellect, and between the ends and the means to those ends. Companion volume: ''Golden Growth.''