Gilbert Keith Chesterton or G. K. Chesterton, was an English writer, poet, philosopher, dramatist, journalist, orator, lay theologian, biographer, and literary and art critic. Chesterton is often referred to as the "prince of paradox." Time magazine has observed of his writing style: "Whenever possible Chesterton made his points with popular sayings, proverbs, allegories—first carefully turning them inside out."

Chesterton is well known for his fictional priest-detective Father Brown, and for his reasoned apologetics. Even some of those who disagree with him have recognised the wide appeal of such works as Orthodoxy and The Everlasting Man. Chesterton, as a political thinker, cast aspersions on both Progressivism and Conservatism, 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." Chesterton routinely referred to himself as an "orthodox" Christian, and came to identify this position more and more with Catholicism, eventually converting to Catholicism from High Church Anglicanism. George Bernard Shaw, Chesterton's "friendly enemy" according to Time, said of him, "He was a man of colossal genius." Biographers have identified him as a successor to such Victorian authors as Matthew Arnold, Thomas Carlyle, Cardinal John Henry Newman, and John Ruskin.