Tin Woodman of Oz, The by L. Frank Baum (1856 - 1919)

The Tin Woodman of Oz is the twelfth Land of Oz book written by L. Frank Baum and was originally published on May 13, 1918. The Tin Woodman is unexpectedly reunited with his Munchkin sweetheart Nimmie Amee from the days when he was flesh and blood. This was a backstory from The Wizard of Oz. (Summary from Wikipedia)