Anton Karl Karas was an Austrian zither player and composer, best known for his internationally famous 1948 soundtrack to Carol Reed's The Third Man. His association with the film came about as a result of a chance meeting with its director. The success of the film and the enduring popularity of its theme song changed Karas' life.

Zithers are a class of stringed instruments. Historically, it could be any instrument of the psaltery family. In modern terminology, it is more specifically an instrument consisting of many strings stretched across a thin, flat body, the topic of this article.