For a long time, cities have worked as a magnet for very different types of people. As centres of trade and commerce, economic production and consumption, education and other forms of human activity, most cities have an extended history as sites of cultural exchange and human diversity. In the past decades, however, cities have become even more diverse, a fact that is adequately captured by the growing literature on ‘super-diversity’. According to Steven Vertovec (2007), who famously coined this term, contemporary cities have seen an increasing diversity of migration in terms of countries of origin, ethnic groups, languages and religions, gender, age profiles and labour market experiences. Complex migration and asylum regimes have further contributed to the process of diversification through the multiplication of immigration legal statuses (civic stratification) (Zetter, 2007; Nash, 2009). Super-diversity has become especially apparent in cities that are designated as ‘global cities’ (Sassen, 1991), on the basis of their ability to draw heterogeneous people from all parts of the world. However, medium-sized and provincial cities and towns in North America and across Europe are also increasingly characterised by a ‘diversification of diversity’ (Erel, 2011), although the scale of diversification can vary drastically between neighbourhoods.

As we can expect continuing migration flows, a high degree of ethnic, religious and socioeconomic diversity will undoubtedly be the norm in 21st-century cities, or at least in some of its neighbourhoods. In this book we are concerned with the question of how urbanites from different ethnic and cultural backgrounds, occupying different socioeconomic positions, speaking different languages and often with different legal statuses, can make a common life together in their city or neighbourhood. This question is paramount because living with diversity can translate into very different forms of interaction. While increasing urban diversity can lead people to communicate and relate to each other across cultural, socioeconomic and other divides, it can also create tensions between groups that were formerly isolated from each other. Some of the longstanding residents complain that they are being overwhelmed by the number of newcomers, experiencing a sense of loss and perceiving increased competition for housing, employment and use of public space. Although super-diverse cities rarely display continuous manifestations of conflicts, counter-reactions in the form of identity politics and an increased demand for cultural assimilation can be observed.