Langleys forfatterskap inkluderer:
- The Land of the White Elephant:Experiences in Indo-Kina (1892)
- In Savage Lands:A Tale of Adventure (1893)
- Historien om Khartoums hjelpeekspedisjon (1894)
- Historien om Uganda-mytteriet (1895)
- The Romance of the Cape Frontier:En historie om piratkopiering og eventyr i det sørlige Afrika (1897)
- The Land of Gold:A Tale of the Mining Days of California (1899)
- Pionerer og patrioter:En side fra Sør-Afrikas historie (1900)
- The Great North Land:A Story of Adventure in the Frozen North (1901)
- The Land of Riddles:A Tale of Adventure in Unknown Africa (1902)
- The New Land of the West:A Tale of Adventure in New Zealand (1903)
- Den røde boken:En historie om reiser og eventyr i Russland (1904)
- The Golden Horde:A Tale of Adventure in Central Asia (1905)
- The Scarlet Runner:A Story of the Land of the Aztecs (1906)
- The Black Panther:A Tale of Adventure in the Brazilian Forests (1907)
- The Lost Continent:A Story of Adventure in Atlantis (1908)
- The Last of the Incas:A Tale of Adventure in Peru (1909)
- The Lone Rider:A Story of Adventure in the Wild West (1910)
- The Fighting Legion:A Tale of Adventure in Ancient Roma (1911)
- The Greenmantle:A Tale of Adventure in Central Asia (1912)
- The Yellow Fog:A Tale of Adventure in China (1913)
- The Lion's Share:A Story of Adventure in British East Africa (1914)
- The Trail of the Tiger:A Tale of Adventure in the Malay Archipelago (1915)
- The White Rajah:A Story of Adventure in Borneo (1916)
- The Sea Rovers:A Tale of Adventure in the Caribbean (1917)
- The Black Buccaneer:A Story of Adventure in the South Seas (1918)
- Mannen fra Madagaskar:En eventyrfortelling i det indiske hav (1919)
- The Diamond Hunters:A Story of Adventure in South Africa (1920)
- The Elephant Hunters:A Tale of Adventure in Central Africa (1921)
- The Golden City:A Story of Adventure in South America (1922)
- The White Goddess:A Tale of Adventure in the Arctic (1923)
- The Black Magician:A Story of Adventure in India (1924)
- The Lost Colony:A Tale of Adventure in the New World (1925)
- The Red Emperor:A Story of Adventure in China (1926)
- The Blue Lotus:A Tale of Adventure in Tibet (1927)
- The Phantom City:A Story of Adventure in the Sahara (1928)
- The Crystal Mountain:A Tale of Adventure in the Andes (1929)
- Den hellige by:En historie om eventyr i Himalaya (1930)
- The Hidden Valley:A Tale of Adventure in the South Seas (1931)