A decade ago no one except geologists had heard of tantalum or 'coltan' - an obscure mineral that is an essential ingredient in mobile phones and laptops. Then, in 2000, reports began to leak out of Congo: of mines deep in the jungle where coltan was extracted in brutal conditions watched over by warlords. The United Nations sent a team to investigate, and its expose of the relationship between violence and the exploitation of coltan and other natural resources contributed to a re-examination of scholarship on the motivations and strategies of armed groups.

The politics of coltan encompass...