The Moomintroll books by Tove Jansson
I've been reading Charlotte these books as I've managed to find copies. In Europe and Japan, the Moomintroll franchise is big business, with animated cartoons and themeparks. We Americans have been lucky enough to be spared all that for once, leaving us only with these lovely illustrated novels of the strange and the familiar, the joyous and the melancholy. Start with either Finn Family Moomintroll, or Tales from Moominvalley, where her inventiveness and her gift for atmosphere meet most satisfyingly.