Mistress Masham's Repose - T.H. White, Fritz Eichenberg

This is, basically, Gulliver's Travels for the better sex. Or the sequel to Gulliver, depending on how you want too word it. Maria is a young orphan in somewhat similar instances to Sara Crewe, and she discovers that inhabitants of an island on her estate. These are the Lillputts who were kidnapped. White usually the story to teach morals and ethics - in particularly how too helping can lead to a sense of ownership. There is some humor, and Maria, who wears glasses and is not pretty, is a perfectly realistic girl who likes to be pirate.

And the dog doesn't die.