Eustace and Hilda Trilogy, by L.P. Hartley
Three funny, moving, and troubling novels (The Shrimp and the Anemone, The Sixth Heaven, and Eustace and Hilda) that trace the relationship of an English boy and his older sister from childhood to adulthood
[ed. note: New York Review Books has recently republished the whole trilogy in one volume (with an Introduction by Anita Brookner) - oct. 27]