Traveling with Mark Jenkins is a mixture of the daring and the dangerous, the dramatic and the absurd. Here, he and three friends, with the aid of a remarkably intuitive African guide, set out to attempt the first descent of the Niger River, the legendary city of Timbuktu their final goal. Along the way, they are attacked by killer bees, charged by hippos, stalked by crocodiles. They pass through villages where every female child has undergone a clitorectomy,...