For much of the African continent archaeological fieldwork is still at an exploratory stage. There must be a great difference between the known archaeological evidence, on which we base our hypotheses, and the evidence that remains to be discovered. There must, in addition, be a veritable gulf between the archaeological evidence we have and the prehistoric human behaviour that we seek to understand. The following paper discusses recent field work in southern Borno in the light of these ideas. This fieldwork aimed to test an hypothesis about human exploitation of the area before 3000 bp but succeeded instead in revealing a substantial number of later sites in a part of an area already previously investigated by the writer. So far as earlier sites are concerned, this new fieldwork suggests that future archaeological exploration should be concentrated on the northern end of the Mandara Mountains and on the deposits at their base. The overall lesson of this fieldwork, however, seems to be that the harder you look, the more you find—although you may not find what you are looking for.