Once upon a time, an Indian writer named Amitav Ghosh set out as an Indian slave, name unknown, who some seven hundred years before had traveled to the Middle East. The journey took him to a small village in Egypt, where medieval customs coexist with twentieth-century desires and discontents. But even as Ghosh sought to re-create the life of his Indian predecessor, he found himself immersed in those of his modern Egyptian neighbors.

Combining shrewd observations with painstaking historical research, Ghosh serves up skeptics and holy men, merchants and sorcerers. Some of these figures are...