This is the second Special Issue of the European Journal of Probation that has its origins in the ongoing work of a European academic network, the COST Action on Offender Supervision, which commenced its work in 2012. 1 The first of the Special Issues, published in December 2014, brought together a collection of articles on the theme of consent and cooperation in the context of offender supervision (see Morgenstern and Robinson, 2014). This was a theme that cut across the work of all four of the Working Groups that make up the COST Action, which address: Experiencing Supervision; Practising Supervision; Decision-Making and European Norms, Policy and Practice. In this second Special Issue, our focus is methodological, and the articles it includes were commissioned from two of the Action's Working Groups, whose members have been engaged in a common purpose for the last two years or so. That common purpose has been the development and piloting of innovative methods for studying aspects of offender supervision practice comparatively. To explain the specific origins of our methodological endeavours, it is necessary to revisit a review of the European literature on the practice of offender supervision that we conducted in the first year of the COST Action (Robinson and Svensson, 2013). This review, which collated overviews of research in 15 jurisdictions, reached a number of general conclusions. The first was that, notwithstanding significant variations between jurisdictions, there was surprisingly little empirical research into the 'everyday' practice of offender supervision in Europe. We further found that, looking across the studies conducted to date, two methods dominated: namely, interviews and surveys. This led us to conclude that extant research on offender supervision in Europe had rather more to tell us about what practitioners say they do, but rather less about what they actually do. A third finding was that the empirical studies conducted to date were overwhelmingly within a single jurisdiction, such that there was almost no comparative research on which to report. Indeed, we found only one study that included a comparative element in its design (Bauwens, 2011). Meanwhile, a parallel review of the research literature by members of the Decision-Making Working Group (Boone and Herzog-Evans, 2013) revealed a particular gap in research in relation to the construction of and reactions to breaches of community