BOOK REVIEW NILE : RIVER OF THE GODS

Exploration at the edge of disaster. River of the Gods : Genius, Courage and Betrayal in the search for the Source of the Nile by Candice Millard.

But the Nile has never yielded its secrets, though traders had long recounted stories of towering mountains and giant lakes that might have given rise to a mighty river. The problem for locals and traders alike was scale - knowing a great deal about one region or stretch of river was far different from knowing the full course of the largest river in the world.

Just how all these lakes and rivers connected, across vast watersheds, no one knew. Explorers since Roman days had tried to follow the Nile upstream to its headwaters. They had all failed. The new strategy was to make an end run instead, by marching inland from the coast.

Burton and Speke and other explorers wound their way like armies on the move, in caravans of 100 or 200 men. Most of the paths they followed had been laid down over the course of centuries by African and Arab traders in Ivory and enslaved people.

The first law of travelers' tales is simply put : The worse, the better. No reader wants to hear of well-made plans or sunsets that paint the sky in glorious reds and purples.

Give us a ship trapped in the ice or desperate wanderers sitting down to a meal of frozen boot. Better yet, give us two Victorian rivals in East Africa, supposed colleagues who were consumed with hate for each other, weak from fever, half-starved and half-blind but nonetheless obsessed with solving a mystery that had mocked the world for 2,000 years.

''River of the God's'' is a lean, fast-paced account of the almost absurdly dangerous quest by those two friends turned enemies, Richard Burton and John Speke, to solve the geographic riddle of their era.

The two men had set out, in 1857, to find the source of the Nile. Candice Millard, formerly a National Geographic writer and editor and the author of a gripping book about Teddy Roosevelt's adventures in South America, has here plunged into another tale of exploration at the edge of disaster.

The search for the Nile's headwaters was not simply a chase for fame and glory, though it was that. Filling in that tantalizing blank on the map would represent a genuine contribution to knowledge as well. It would not come easy.

Burton, six years olders than Speke and more experienced, was the expedition leader. Speke was second in command. They should have worked well together.

Speke was a skilled surveyor and a geographer. Burton an astonishingly gifted linguist. Both were fearless and ambitious, but they had little else in common.

Burton was a scholar and an adventurer - the first Englashman to travel to the forbidden city of Mecca [ disguised as a Muslim ], a linguist who speke 25 languages, and a tranlator who would one day bring the Kama Sutra and ''Arabian Nights'' to a vast audience of titillated, scandalized Victorians.

Speke was a more conventional character, a soldier from an aristocratic family, a big-game hunter and, in one acquaintance's admiring description, ''a fine, manly, unaffected specimen of the Englashman.''

They quickly became fierce enemies. Yoked together in pursuit of the same goal, they devoted vast stores of energy to denouncing each other, as if ''Who's Afraid of Virginia Woolf?'' had been rewritten to feature a pair of mismatched Victorian explorers.

Almost from the start, Burton and Speke found themselves tormented by a host of mysterious pains and illnesses. Three months into their journey, they came to a 7000-foot-tall mountain range.

''Trembling with ague, with swimming heads, ears deafened by weakness, and limbs that would hardly support us,'' Burton wrote, ''we contemplated with dogged despair the apparent perpendicular path.''

Speke needed the support of three men just to keep on his feet. Then his fever boiled over and he began raving in delirium. Porters took away his weapons, for everyone's safety. The expedition's supply of food, which was meant to last a year, had nearly run out. There were no villages nearby to trade with and scarcely any game to hunt. Desperate for protein, the travelers took to eating ants.

The World Students Society thanks review author Edward Dolnick.