The material for this book was collected between 1961, when I started my intermittent fieldwork among the Berti, and 1986, when I was in the field for the last time. I visited the Berti area on six occasions and my stays there stretched from three to nine months. I spent in total a little over three years in the field. Most of the time, I lived in the village of Dūda, three kilometres south of the market and well at Madu, in the northern part of the Berti area along the track connecting Melit and Malha. My wife and I had our own household there in 1965 and then again in the late 1970s and early 1980s, before the village was temporarily abandoned during the drought in the mid 1980s. Its inhabitants lost virtually all their donkeys and, being unable to transport water to the village, camped in the vicinity of the well in Madu where we joined them in 1986. In 1980, we spent two months in the village of Watkani, about six kilometres south of Melit and, in 1986, we lived for three months in Am Ja 'āl, about ten kilometres east of the market and wells in Sayah.

My field trips to Darfur were sponsored by the Czechoslovak Academy of Sciences, the International African Institute, the Queen's University of Belfast, the Carnegie Trust and the Social Science Research Council. I am very grateful for the generosity of these bodies.