John Hemming, historian and former director of the Royal Geographical Society, tells the story of the Cinchona tree - from the medicinal uses of its bark to cure malaria by Ecuadorian Indians - to becoming the essential ingredient in gin-and-tonic. Rubber, though used by Amazonian Indians, became the durable product we know only in the 19th century. It produced flamboyant wealth for Manaus and its rubber barons, but hardship for the seringueiros and Indians forced to collect it. John Hemming gives new interpretations to the removal of rubber from the Amazon in the 1870s and the subsequent collapse of the rubber boom.

His new book "Tree of Rivers. The Story of the Amazon" describes the passionate struggles that have taken place in order to utilise, protect and understand the world's greatest expanse of tropical rainforest. Published by Thames & Hudson 2008.