Most agricultural projects initiated by the government of Zaire in the small-farm sector during the last two decades to improve a worsening food supply situation have failed mainly as a result of limited knowledge about constraints affecting the development of the sector. This study was undertaken to fill this gap. The study area is located in the Zairian Basin, which is part of a tropical rain forest zone. The zone includes large parts of Equateur, Haut-Zaire, Sud-Kivu, Maniema, Kasai Oriental, Kasai Occidental, and Bandundu regions, and a small part of the Bas-Zaire region. The Basin also extends beyond the Zairian boundaries to include a part of the Congo.