Mr. Tinker was an inventor who lived in the town of Evna. He was a partner in the firm of Smith & Tinker.
History
Smith and Tinker were wonderful inventors, their creations include Tik-Tok the machine man and the iron giant.
One day Mr. Tinker made a ladder so tall that he could rest it against the moon while he picked stars for the king's crown. He liked the moon so much that he pulled up the ladder after himself and stayed there. (Ozma of Oz)
Background
Tinker never appeared in any of the "Famous Forty" Oz books, but his story is told by Tik-Tok in Ozma of Oz.
In 1985 James Howe published a modern Oz book about him, titled Mister Tinker in Oz.