Yellow Jack is a 1934 docudrama play starring James Stewart and produced by Guthrie McClintic that was later adapted into a 1938 Hollywood movie by the same title. Both were co-written by Sidney Howard and Paul de Kruif (the former a Pulitzer- and Oscar-winning playwright and screenwriter; the latter a well-known microbiologist and author). The play is the work of Sidney Howard and is based on a chapter in Paul de Kruif's 1927 book Microbe Hunters.