The French social scientist Arnold van Gennep (23 April 1873 – 7 May 1957) most famously defined the concept of rites of passage in his book "" ("The Rites of Passage"), first published in 1909. Van Gennep studied ethnographic reports from various parts of the world that described rites of passage. He concluded that they are universally structured even if the rites of passage themselves differ significantly in character between societies and cultures.