In the late 1800s, missionaries and government officials stationed along the south coast of Papua New Guinea began to observe large fleets of indigenous Motu sailing ships coming and going out of present-day Port Moresby. Each year the women of nearby villages manufactured tens of thousands of clay pots to be loaded onto the ships that men built, then sailed with their cargos westward some 400 kilometers. Upon arrival at prearranged destination-villages in distant lands to the west--lands populated by peoples speaking foreign languages--the pots together with the shell valuables were...