Philippa Pearce. Tom's Midnight Garden.
Astrid Lindgren. the Pippi Longstocking books
Laura Ingalls Wilder. Little House on the Prairie etc
Tove Jansson's Moomin books
Susan Cooper. The Dark is Rising etc
Ursula Le Guin. A Wizard of Earthsea etc
Clive King. Stig of the Dump
Lloyd Alexander's Taran series
Madeleine L'Engle. A Wrinkle in Time
Norton Juster. The Phantom Tollbooth
Anna Sewell. Black Beauty

Stop me before I get carried away. I could go on forever.