L. Frank Baum wrote The Patchwork Girl of Oz and thirteen other Oz books including The Wonderful Wizard of Oz which eventually got made into a movie (The Wizard of Oz).
Members of the Dutch Mafia know that L. Frank Baum lived near Holland, MI while he wrote many of these novels.
Eventually he moved to Hollywood, tried to turn his books into movies and failed. Oddly though, one of his jackets was worn by the wizard of Oz in the movie.
A side note:
I suspect that my esteemed fellow noder may be wrong about calling Baum an "extreme right-winger." He certainly would be regarded as such today, but it wouldn't surprise me if his thought on Indians actually represented progressive, liberal thought for his period (late 1800s, early 1900s).
Baum's wife (I think her name was Maude...) grew up in a house that was both anti-slavery and feminist. Susan B. Anthony (a major early feminist) stayed overnight at her house.
Both Baum and his wife were enthusiastic about the Temperance Movement (which was progressive for it's time). Also they were experimenters with an alternate religion of the period, Theosophy. Theosophy imagined that "secret masters" of the past attempted to bring humanity to enlightenment throughout history (as well as the present day). It included reincarnation and channeling spirits via a medium among it's practices.
Baum's progressive, utopian style of thought had it's effect on the Wizard of Oz, a story he created in an attempt to write a story that did not include violence or other things he viewed as harmful.
If anything, Baum seems more left than right. Where his views on Indians come from, I'm not totally sure.
An unnerving possibility as to why Baum might support the exterminantion of American Indians is the popularity of eugenics during the period in which he lived. Eugenics, the idea that one could (and should) improve the human race by breeding, was quite big amongst liberal, progressive thinkers during the latter portion of the 19th century and first half of the 20th (remember Hitler? He loved eugenics. Ironically, many of his ideas on how to do it came from the U.S.).
Many U.S. politicians and intellectuals advocated sterilizing the "unfit"--by which they meant drunks, criminals, and the unemployed... and immigrants... and minorities... Baum's thoughts on Indians may be a manifestation of this common idea of the period.