On May 17, 1900, "The Wonderful Wizard of Oz" was first published by L. Frank Baum with illustrations by William Wallace Denslow in Chicago. A short excerpt from the article:
"2. The author and his “Oz” co-creator had a major falling-out.
When “The Wonderful Wizard of Oz” debuted, it was praised for its lavish illustrations, created by Philadelphia-born artist William Wallace Denslow. Baum and Denslow met in Chicago in the 1890s and Denslow did some drawings for “The Show Window,” Baum’s trade magazine, before the two teamed up on “Father Goose,” the surprise 1899 best-seller. Their next project, “Oz,” for which they shared the copyright, quickly became a best-seller; however, the pair’s relationship soured, with each man believing he deserved the credit for the book’s success. Although they released one more children’s book together, 1901’s “Dot and Tot of Merryland,” they never collaborated on another “Oz” book. After clashing over royalties from a popular 1902 musical production called “The Wizard of Oz” (the first time “wonderful” was deleted from the title), the men parted ways. Denslow continued to work as an illustrator (the Scarecrow and Tin Man characters from “Oz” showed up in some of his designs) but his career eventually went into decline after he developed a drinking problem. He died in 1915 in New York, four years before Baum."