In the now nearly 20 years since its official foundation, a lot has been written about the Common European Asylum System (CEAS). The purpose of this review was to systematically collect, organize, and analyse – both quantitatively and qualitatively – this vast body of existing knowledge in order to inform the field research to be carried out within other work packages of the CEASEVAL project. The aim of this working paper is to describe the review process in more detail and to summarise and discuss the most important results as well as their implications for future research. A number of key themes were identified including: harmonization and transposition of CEAS, solidarity and responsibility sharing, externalization and solidarity with third countries, politicisation of the Refugee Crisis, multi-level governance and the role of non-state actors. Overall, the results of our review suggest that although the existing body of literature is already quite vast, more in-depth analysis across different administrative levels, including case studies as well as comparative research is needed to fully understand the complex dynamics underlying the development of a (more) common approach and policy in the field of asylum.