Sky Island: Being the Further Adventures of Trot and Cap'n Bill after Their Visit to the Sea Fairies is a children's fantasy novel written by L. Frank Baum, illustrated by John R. Neill, and published in 1912 by the Reilly & Britton Company[1]—the same constellation of forces that produced the Oz books in the first decades of the twentieth century.

Trot, a little girl who lives on the coast of southern California, meets a strange little boy with a large umbrella.

In Sky Island, as in Oz, no one can be killed or suffer pain, but that doesn't mean one is safe: the Boolooroo's method of punishing disobedience in his subjects is to slice two of his victims into halves using a huge guillotine-type knife and then join the wrong halves back together, creating very unhappy asymmetrical mixed people.

Polychrome also discovers another quirk in the Pinkies' law: whichever person in the kingdom has the lightest skin shall be Queen.

Trot then uses her new power as Queen to mount an invasion of the Blue Country in order to recover the magic umbrella from the Boolooroo.

Ultimately, with help from a Pinkie-witch, a friendly Blueskin citizen (there is one), and the goat itself, she manages to rescue Cap'n Bill and capture the Boolooroo.

Baum attempted to launch two other juvenile novel series in the same 1911–12 period, The Flying Girl and The Daring Twins, neither of which was a long-term success.