The Road to Oz by L. Frank Baum [Wizard of Oz #5]

In THE ROAD TO OZ, Dorothy meets the Shaggy Man, and while trying to find the road to Butterfield, they get lost on an enchanted road, having all sorts of adventures along the way. As they travel they meet the rainbow's daughter, Polychrome, and a little boy, Button-Bright.

Lyman Frank Baum (1856-1919) was an American writer of children's books, including THE WONDERFUL WIZARD OF OZ and thirteen sequels.  In addition to his Oz books, Baum wrote dozens of other books and short stories, often set in mythical lands.