International development planners need to incorporate rural people's extensive historical experience with colonial, state and international development projects into their project feasibility documents. A comparison of four planning documents prepared in Guinea during 1987-93 with historically informed field research demonstrates how the documents overlooked important factors in understanding local techniques in soil management and in women's organizational experiences. While many projects employ participatory methodologies to gather background information, they continue to emphasize technical and descriptive data and overlook important historical changes in the social and economic conditions that affect natural resource management strategies.