Skylark DuQuesne (pronounced Ducane) was the final novel in the epic Skylark series by E. E. Smith. Written as Dr. Smith's last novel in 1965 and published shortly before his death, it expands on the characterizations of the earlier novels (written 1919 - about 1938) but with some discrepancies (some of which may relate to unwritten background developments). The most significant point is that Dr. Marc DuQuesne, the major villain of the three previous novels, is shown to have matured, reformed, and offered a chance at what amounted at pardon for his prior crimes against the heroes.
Skylark DuQuesne was first serialized in IF Worlds of Science Fiction beginning in June 1965 before being published in 1966 by Pyramid Books. The novel was nominated for the Hugo Award for Best Novel in 1966.