This article provides a general background to the case studies in this Special Issue by highlighting some general themes in the history of migration to coalfields worldwide. All over the world, mining companies have struggled with labour shortages and had to find ways to recruit sufficient numbers of mineworkers. The solutions adopted ranged from the involvement of part-time peasant miners, organized mediation by labour contractors, and systems of forced labour, to state regulation of national and international migration. The importance of these kinds of "intervening institution" in mobilizing labour for the coalmines is illustrated by examples from different parts of the world. Efforts to find new workers for the mines often resulted in the recruitment of ethnic groups of a lower social status, not only because they were rural and unskilled, but also because they were considered inferior from a cultural or ethnic viewpoint. In this respect there was a huge difference from the migration and settlement of skilled miners, like those from Britain and other countries. Ethnic differences were often closely related to differences in skill and social status. Although there are many instances of inter-ethnic solidarity and cooperation, depending on the time-frame and circumstances, these differences could have a profound effect on social relations in mining communities.