"Nothing obsessed explorers of the mid-nineteenth century more than the quest to discover the source of the White Nile. It was the planet's most elusive secret, the prize coveted above all others. Between 1856 and 1876, six larger-than-life men and one extraordinary woman accepted the challenge. Showing extreme courage and resilience, Richard Burton, John Hanning Speke, James Augustus Grant, Samuel Baker, Florence von Sass, David Livingstone, and...