Gilbert Keith Chesterton (May 29, 1874 – June 14, 1936) was an influential English writer of the early 20th century. His prolific and diverse output included journalism, philosophy, poetry, biography, Christian apologetics, fantasy, and detective fiction.

Chesterton has been called the "prince of paradox." He wrote in an off-hand, whimsical prose studded with startling formulations. For example: "Thieves respect property. They merely wish the property to become their property that they may more perfectly respect it." He is one of the few Christian thinkers who are equally admired and quoted by both liberal and conservative Christians, and indeed by many non-Christians. Chesterton's own theological and political views were far too nuanced to fit comfortably under the "liberal" or "conservative" banner. And in his own words he cast aspersions on the labels saying, "The whole modern world has divided itself into Conservatives and Progressives. The business of Progressives is to go on making mistakes. The business of the Conservatives is to prevent the mistakes from being corrected." He routinely referred to himself as an "orthodox Christian," and came to identify such a position with Catholicism more and more, eventually converting to the Catholic Church.