It is more than 50 years since Alan Moorehead wrote The White Nile, his magisterial study of efforts to find the source of the great river that rises in the lakes of central Africa and flows down through the swamps of southern Sudan to bring life to the cotton fields of Egypt, before reaching the Mediterranean.

Having written biographies of David Livingstone and Henry Morton Stanley, two of the quintet of great Victorian explorers of the Nile (the others being John Hanning Speke, Richard Burton and Samuel Baker), Tim Jeal is well placed to bring this story up to date.

While mindful of some of the absurdities and cruelties of their missions, Jeal is refreshingly sympathetic to the anti-slavery ideals of men such as Livingstone, as well as to the old-fashioned romanticism of Burton and Speke – before such qualities were overtaken by more political and commercial considerations in the age of late Victorian imperialism.