Denslow was born in Philadelphia, but by the 1890s had moved to Chicago where he met L. Frank Baum. They first connected professionally in 1898, when Baum used Denslow illustrations for his trade journal The Show Window. In the same year, Denslow contributed two pen-and-ink sketches to Baum's By the Candelabra's Glare. The two next collaborated on Father Goose, His Book before working together to create The Wonderful Wizard of Oz. The next year they published Dot and Tot of Merryland, but their partnership quickly dissolved after disagreements over a stage production of The Wizard of Oz.