David Unaipon was a prominent Australian Aborigine who became an important voice for Aboriginal welfare during the 1920s and 1930s. He used his education and public-speaking abilities to gain support from Aborigines and to earn an audience with government leaders.
Unaipon was also an inventor and writer. One of his earliest inventions in 1909 was an improved sheep-shearing tool. Many of his other inventions were motors and wheels; he also tried to invent a perpetual motion device. Unaipon began writing actively in the late 1920s and 1930s. While some of his early works were uncredited, he published "Aboriginal Legends" in 1927 and "Native Legends" in 1929.