William Halse Rivers Rivers, FRCP, FRS was an English anthropologist, neurologist, ethnologist and psychiatrist, best known for his work treating World War I officers who were suffering from shell shock. Rivers's most famous patient was the poet Siegfried Sassoon, with whom he remained close friends until his own sudden death. Rivers was a fellow of St John's College, Cambridge, and is also notable for his participation in the Torres Straits expedition of 1898 and his consequent seminal work on the subject of kinship.