W. W. Denslow is the illustrator and collaborator on author L. Frank Baum’s The Wonderful Wizard of Oz. Mr. Denslow started his career as an editorial cartoonist, later moving on to poster art and eventually making the transition to children’s illustration. He had collaborated with Baum thrice before creating Oz, on the title’s By the Candelabra’s Glare, Father Goose: His Book, and Dot and Tot of Merryland. Following the 1902 stage adaptation of The Wizard of Oz there were a few quarrels about royalty shares, which caused the Denslow–Baum partnership to split up. Mr. Denslow continued to illustrate and write children’s book and even went on to create one of the earliest super-powered protagonist in a comic strip, Billy Bounce.
His fluid ink work, along with the reproduction techniques of the time make his illustrations beautiful and charming. A good place to see more of his work is on wikimedia and you can read some of his children’s book over at Project Gutenberg.