When Captain Cook arrived in New Zealand waters in 1769, his sailors and the Maori who met them began to trade almost immediately. When two civilizations meet, trade has a major role to play - for good and for bad.

Paul Seabright investigates the cultural impact of trade. And, in a story from China, he hears how the social consequences of trade contacts made many centuries ago can still be seen today.

Producer: Chris Ledgard.

First broadcast on BBC Radio 4 in January 2018. Show less