‘Naval, air, space, and modern warfare’ looks into each realm in turn. Naval warfare has been conducted on three classes of ship—galleys, sail, and steam—each with its own characteristic technologies and ways of warfare. Unlike galleys and sailing ships, airplanes as platforms for warfare were custom-designed from the outset for their particular weapons and missions. The origins of space warfare paralleled aviation in many ways. Both airplanes and spacecraft are dual-use technologies that found applications from both demand pull and technology push. Finally, total warfare is discussed and how since World War II nuclear technology has deterred great-power wars.