The river Niger, a source of life and danger for the people in impoverished eastern Mali, is also the origin of elaborate mythology. From his travels through Mali and down the Niger in a dugout canoe, Jean-Marie Gibbal has created a personal documentary of the cultures of the region. The result is at once an ethnography of cultures in crisis and a poetic evocation of the environment and people he encountered.

Gibbal portrays the river as the dominant, cohesive force among people in the face of social and environmental strife. He focuses on the Ghimbala healing cult, which centers...