Alan Moorehead wrote two brilliant books in the 1960s, The White Nile and The Blue Nile. Together, they stood as the most reliable, most readable account of the European search for the sources of the Nile, until Tim Jeal set himself the task of writing a single volume that would update Moorehead's books.

The whereabouts of the Nile's sources was the single greatest geographical mystery of the 19th century. The story of how that mystery was solved in the decades following 1856 mixes questions of politics, economics and social history, among them the rise of the British empire, and of radical Islam, and the abolition of slavery. Extraordinary characters such as the polymath Sir Richard Burton, the missionary Dr David Livingstone, Mutesa the king of Buganda and the journalist Henry Stanley play key roles in the drama.

Jeal approaches this rich material having already won awards for his biography of Stanley and he tells this bigger story well enough for his volume to replace Moorehead's duet. He has a sure grasp of the range of characters, of the terrain they crossed and of the issues of the time. And he has managed to dig up some new material, including the original manuscript of Burton's travelling companion, Speke.

This new material shows Speke to be a much rounder and more sympathetic character, just as Jeal's earlier book showed Stanley to be less of a brute than previously assumed. He also brings into focus the people who made the whole thing possible, the guides and porters to whom none of this was a mystery and who have, traditionally, been written out of such accounts.

For all his scholarship, there are still mistakes. The book opens  the second sentence  with a false assertion: Alexander the Great never visited the Temple of Amun in Luxor, instead going to the Temple of Ammon in Siwa. Elsewhere, it is suggested that the earlier traveller Mungo Park was speared to death, but in fact he drowned in the Niger. Also less successful is Jeal's concluding chapter, which considers the consequences of exploration, from the Belgian colonisation of the Congo to the Khartoum government's recent attack on Darfur. The coverage is too brief, making the conclusions seem unjustified. Explorers of the Nile would have been a better book without that last chapter, but it remains a masterful account of one of the most exciting periods of exploration.