This volume contains abstracts and papers presented at the second Danish Sahel Workshop helld at Sandbjerg Manor in 1990. The papers cover natural and social sciences, such as improved utilisation of tree legumes, degradations and desertification, afforestation techniques and problems, ecological monitoring and remote sensing techniques, animal counting in Senegal, the political economy of agricultural development in Burkina Faso, research and development in the Red Sea area, the economic potential of the semi-arid areas, as well as accounts of the research sponsored by DANIDA, integrated projects in Mali and Senegal and the Danish activities with control of parasitic diseases in Africa.