Delilah Darling is in the Library by Jeanne Willis
'My name is Queen Delilah and I come from a land far, far away, really I do.' My mother says, 'Really you don't, darling.' But if Delilah did rule the world, what a fun place it would be! Except she would be the first to tell you that she's not naughty at all - you see, Delilah is a queen in her own country and the rules are quite different there! Her first adventure finds her in the library creating utter chaos, much to the despair of the librarian, Library Anne, but to the huge delight of everyone else!