International Security, Winter 2010/11:

The Rise of Muslim Foreign Fighters: Islam and the Globalization of Jihad
...The purpose of this article is threefold: first, to establish foreign fighters as a discrete actor category distinct from insurgents and terrorists; second, to present new empirical information about Muslim foreign fighters; and third, to propose a plausible hypothesis about the origin of the phenomenon. The analysis is based on a new data set of foreign fighter mobilizations, a large collection of unexplored primary and secondary sources in Arabic, as well as personal interviews with former foreign fighters conducted in Britain, Jordan, Pakistan, Palestine, and Saudi Arabia.

The scope of the article has two important limitations. First, the conceptual focus is on movement formation, not on general mechanisms of foreign fighter mobilization. I do not formulate a universal theory of foreign fighters, predict rates of recruitment, or explain individual recruitment. Second, the empirical focus is on the Muslim world. A study of Muslim foreign fighters arguably has intrinsic value, because Muslim war volunteers are much more numerous and have affected many more conflicts than have foreign fighters of other ideological orientations. In addition, their involvement in major conflicts such as Iraq and Afghanistan, as well as their role in facilitating al-Qaida recruitment, make them a particularly significant challenge to contemporary international security....