Leo Lucassen is Professor of Global Labour and Migration History at Leiden University and director of the International Institute of Social History in the Netherlands (IISH). He has long contributed to the debate on migration, with (The Immigrant Threat. The integration of old and new migrants in Western Europe since 1850, The University of Illinois Press, 2005; with D. Feldman & J. Oltmer (eds.), Paths of integration. Migrants in Western Europe (1880-2004), Amsterdam, 2006; with J. Lucassen & P. Manning, eds., Migration History in World History. Multidisciplinary approaches, Brill Publishers, 2010; The Encyclopdia of Migration and Minorities in Europe Cambridge University Press, 2011, with K.J Bade et al.).