Headquarters Nights: A Record of Conversations and Experiences at the Headquarters of the German Army in France and Belgium by Vernon Lyman Kellogg

William Jennings Bryan was horrified by the mass slaughter of World War I. He came to believe that German militarism that led to the war was based on the "survival of the fittest" doctrine from the theory of evolution. Bryan came to this conclusion largely as the result of reading Kellogg's book. Vernon Myman Lyman Kellogg was an American entomologist (Entomology - scientific study of insects). Full-text of "Headquarters Nights" is available above.