It’s last light in the valley, and the sound of rushing water drowns out all others. I walk the river’s edge with my dog, Mosi, whose inability to hear over the cascade makes him nervous. Despite his impressive size, he trots sheepishly at my heels. Ostensibly we walk to fish, but really we move at the urging of naturalists long since passed—of John Burroughs and John Muir, of Loren Eiseley—and of my parents, Norman and Paula, who are alive today but live far from this Kenyan vale. Walk in the woods, their voices advise, along the banks of a river where, in the blue end of a day, you may find the rhythms that elude you. There, among the fish