Book excerpt: An international bestseller this novel follows an unforgettable journey from the demure gentility of turn-of-the-twentieth-century England into the heart of darkness. In 1904, the young lepidopterist Thomas Edgar arrives home from a collecting expedition in the Amazon. His young wife Sophie is unprepared for his emaciated state and, even worse, his inability - or unwillingness - to speak. Sophie's genteel and demure life in Edwardian England contrasts starkly with the decadence of Brazil's rubber boom, as we are taken back to Thomas's arrival in the Amazon and his search for a mythical butterfly. Up the river, via the opulent city of Manaus - where the inhabitants feed their horses champagne and aspire to all things European - Thomas's extraordinary, and increasingly obsessed, journey carries him through the exotic and the erotic to some terrible truths. Back home, unable to break through Thomas's silence, Sophie is forced to take increasingly drastic measures to discover what has happened. But as she scavenges what she can from Thomas's diaries and boxes of exquisite butterflies, she learns as much about herself as about her husband.