After an astonishing career as explorer and missionary, Dr David Livingstone disappeared back into his beloved Africa for one last time in search of the source of the Nile. He believed that the river sprang from four mysterious fountains which had been known to the ancient Greeks. Livingstone faced his task with unparalleled bravery but he was frail and eventually he died on the shores of a swampy lake.
Over a century later, Colum Wilson and Aisling Irwin, husband and wife, retraced his last journey on foot, canoe and bicycle. They found vivid evidence of his continuing legacy to East Africa - and haunting echoes of his spirit.
Colum Wilson spent his childhood in Scotland and Ireland, and was educated at Shrewsbury School. After a short army commission he studied at Durham University. He trained initially as a journalist and then took a master's degree before becoming a civil engineer, specialising in water and in development issues. He has worked in Sudan, Kyrgyzstan and Tanzania.
Aisling Irwin was educated at King Edward VI Camphill school and Wycliffe College, reading chemistry at Durham University, and the history and philosophy of science at London University. She has worked as a journalist for Times Higher Educational Supplement and as a science correspondent for the Daily Telegraph.