In late 1937, Simak returned to science fiction. He was a regular contributor to "Astounding Stories" during the Golden Age of Science Fiction (1938–1950). His first publications, such as "Cosmic Engineers" (1939), were in the style of the earlier superscience type. He soon made his own style, which is usually described as gentle and pastoral. During this period, Simak also published a number of war and western stories in pulp magazines. His best known novel may be "City", a collection of short stories with a common theme of mankind's eventual leaving from Earth.