Hughes, Alfie's World. If you have small children and you haven't discovered English author/illustrator Shirley Hughes, you should check her out. Cancer children in particular will appreciate the safe, homey domestic world of Alfie and his little sister, Annie Rose.
Stevenson, A Child's Garden of Verses. Sweet, lulling poems about playing by the sea shore, imaginary worlds, and all the flights of fancy that Cancer loves, but always with home to come back to.
Dicamillo, The Miraculous Journey of Edward Tulane. Written by a Newbury Award-winning master. An absolutely heartbreaking, tender tale about the power of love, that has inspired a devoted following.
Stewart, The Gardener. A Caldecott winner, and a gentle story of gardening, love, and family. Written by a husband and wife team (she wrote it, he illustrated it).
