Based on the long-established American law and literature movement, the interdisciplinary research field of 'law and literature' is also beginning to hesitantly establish itself in Europe. The German Collaborative Research Centre (SFB) 1385 'Law and Literature' has provided an important impetus for this development. The present work builds on the latter and aims to develop a contrastive interdisciplinary research method ('legal counterfactual') that claims to offer a methodological basis for the further development of the young research field of 'law and literature'. The particular focus herein is on law in literature. An overview of the heterogeneous research approaches in Italy, France, Belgium, and Germany is first provided. Thereafter, the focus shifts to a theoretical examination of the methodological concepts of interdisciplinarity and counterfactuality on the one hand, and the specific approaches to the text - namely discourse and hermeneutics - on the other. Based on these theoretical 'building blocks', the dividing lines between legal and literary studies are drawn in the first step, to identify the resulting intersections in the second step: the written text as a common working basis on the one hand, and hermeneutics and discourse as a means of analysing texts on the other. The legal discourse in the texts is methodically extracted and contrasted with the real-world legal texts in a juxtaposing manner. The aim of this counterfactual contrast is to determine the degree of correspondence between diegetic and real law. To consolidate this method of legal counterfactuals, five works of contemporary literature are tested and demonstrated in practice: La décision (2022) by Karine Tuil, Sworn Virgin (2014) by Elvira Dones, Unorthodox (2012) by Deborah Feldman, Repenti (2017) by Claude Chossat, and A Slap in the Face (2016) by Abbas Khider. The selection of works is motivated by an interest in touching on different areas of law that have received little attention in interdisciplinary law and literature research to date, such as French anti-terror law, the customary law of the Albanian Kanun, Talmudic law, Corsican feudal vendetta law, and German asylum law.