Jansson's Grandmother (she's given no other name) is crotchety and wise and foolish and loving. She smokes cigarettes and breaks into a neighbor's house. No cookie-baking for this grandma. She's a renegade. But she also understands her granddaughter Sophia, pushes her and puts her in situations where she is bound to succeed.
Grandmother also levels with herself and with others (when she's not lying, that is). Here she is after the break-in:
"My dear child," said Grandmother impatiently [to Sophia], "every human being has to make his own mistakes." ... Sometimes people never saw things clearly until it was too late and they no longer had the strength to start again. Or else they forgot their idea along the way and didn't even realize that they had forgotten."
That's the kind of gem Jansson strews about for us through the pages of this slim and lovely book, all of it amidst a natural world (an island in the Gulf of Finland) that is as beautiful as it is dangerous.