Dorothy and the Wizard in Oz is the fourth book of the series. An earthquake splits open the earth under Dorothy, and she, her kitten Eureka, her cousin Zeb, and a horse named Jim fall into a city of glass. They are joined by the Wizard of Oz and nine piglets, and must wander through dangerous lands trying to find their way home. In their journeys, they must cope with invisible bears, flying gargoyles, and a den of young dragons. But rescue, and a return to the Emerald City, are not the end of Dorothy's troubles. Dorothy and the Wizard in Oz was published on June 18, 1908 and reunites Dorothy with the humbug Wizard from The Wonderful Wizard of Oz (1900). L. Frank Baum is best known for his "Oz" books, starting with The Wonderful Wizard of Oz. Baum wrote a total of fourteen Oz books during his lifetime, plus a collection of stories. The series was continued by others after Baum's death.