Fresh-caught fish may be part of the meal plan, but African Angler encourages a catch-and-release policy for leviathans. Ahmed, the Bushera's guide, leaps into the water to unhook Dermott's catch; it must weigh more than a hundred pounds. Forgetting all about the crocodile population, Dermott wades in to help. They cut the line, flush water over the gills, and heave the creature toward the deep. It swims off weakly, looking blind and prehistoric with its luminescent golden eyes and tiny mouth out of proportion to the rest of its huge, humped body.

Fishing is usually all about patience. This is instant gratification. Standing on a granite ledge, I see more flashes of silver. Within minutes we each have hits, and I land a perch that stretches half my height.

Back aboard the Gazal, Moursi confides to me that he once lived in a palace in Jeddah, Saudi Arabia, and cooked for King Fahd's uncle; he wins over the epicureans among us by baking a twenty-pound perch for supper. The skin is crispy and black, and the soft white flesh tastes lightly of cumin. As darkness falls, we hear fish leaping and jackals calling. The desolation is as delicious as our dinner. With the desert at our back and the lake's plenty at our feet, it is easy to imagine the anxiety and wonder of the ancient world, where a river could become an ocean and where a single fish might feed a multitude.

On my desk in Cairo, I keep a nineteenth-century photograph of the Nile in full flood; the river stretches toward the horizon, where waves lap at palm trees dominated by the Giza Pyramids. Mud left by this temporary sea turned a desert valley into fertile farmland, making civilization possible in hot, rainless Egypt. Even if travelers didn't worship Isis or Osirus or believe in the pharaoh's divinity, they witnessed the Nile's miracle with awe. In the fourth century b.c., Herodotus marveled at "villages marooned like islands in the Aegean." Unable to sow crops, Egyptian farmers navigated the floodplains in papyrus ships and spent three months a year building tombs and temples while waiting for their fields to dry out.

Half the population of Egypt is too young to remember what the world looked like when the Nile flooded, yet Cairenes heed its promise of relief and renewal. On hot summer nights, families escape stifling apartments by sleeping in cars on the river's breezy concrete bridges. In this crowded, chaotic capital, men fish and young couples court along the calm Nile riverbank. On Fridays and public holidays, overloaded ferries transport singing party-makers from Cairo to Qanatir, the point where the Nile branches into the delta. These outings echo the ancient Feast of Opet, when temple priests took golden statues of Mut and Amun from their respective sanctuaries and placed them on sacred boats for a conjugal river visit before returning them to the solitary gloom of the naos, the temple's innermost shrine.

With its flood contained behind the High Dam, the Nile in Cairo is both tame canal and schizophrenic time machine. Water-skiers and sailboarders share it with fishermen out of a tomb painting. Between banks of modern skyscrapers, two-masted feluccas ferry pyramids of grain from green islands where farmers still live in mud-brick houses that have hardly changed over the millennia. On the Giza corniche, Egyptian weight lifters pump iron in a floating Gold's Gym modeled after Cleopatra's barge, and Nubian men dressed like King Tut's soldiers welcome guests to The Pharaohs, twin floating restaurants with belly dancing shows.