The fact that many recent papers and political views concern the concept of a digital divide attests to fears of inequalities generated by the widespread diffusion of ICTs. Yet the digital divide is a relatively vague concept that encompasses a variety of issues and often justifies divergent policies. This paper considers the opportunity to turn it into a scientific subject, whereas until now it has been an indeterminate object widely used in the political arena. The first part reviews the concept, while the second part focuses on its geographical dimension by sorting the inherent problems by geographical scale (OECD countries, rich/developing countries, urban/rural areas) and then briefly highlighting the main research issues.