Fatu-Hiva - Back to Nature is a book published in 1974 by archaeologist and explorer Thor Heyerdahl detailing his experiences and reflections during a 15-month stay on the Marquesan island of Fatu Hiva in 1937–38.
The book was based on Heyerdahl's original report På Jakt efter Paradiset (In Search of Paradise), which was published in Norway in 1938, but because of the outbreak of World War II was never translated and rather forgotten.
They nominally had an academic mission, to research the spread of animal species between islands, but in reality they intended to "run away to the South Seas" and never return home.
It was in this setting, surrounded by the ruins of the formerly glorious Marquesan civilization, that Heyerdahl first developed his theories regarding the possibility of pre-Columbian trans-oceanic contact between the pre-European Polynesians, and the peoples and cultures of South America.
Initially, the Heyerdahls found life on Fatu Hiva to be idyllic, what with the abundance of fruit trees and readily available unpolluted river water.