The topics of ‘punishment’ and ‘prisons’ have filled libraries for years. An overview of European research on these issues would require at least two books (see e.g. Daems et al. 2013, on ‘European penology’). This chapter is therefore necessarily selective and based on the authors’ personal interests, expertise and the languages they know (Dutch, French, English, German). In line with this book’s general aim, we will focus on comparative or specifically European approaches. Following Nelken’s (2007) argument concerning comparative research, we will look at both similarities and differences within European penological research, linked to its history, and to the diversity of penal policies. This will then be further developed with regard to prison research.