This introduction to Marc Leroys’s sets out to underscore the importance of a sociology of tax law that, despite being unjustly neglected, constitutes a crucial interface between the sociology of law and the sociology of economic action. Increasingly visible in a system as complex as ours, this link calls for the theoretical use of tools of inter-systemic analysis, the empirical use of tools of public opinion analysis and the conceptual use of tools of comparison between different legal systems. That is because a sociology of tax law must consider the gradual loss of relevance of the conventional national horizons of tax policies. Correspondingly, it must also consider the profound influence exerted by supranational organisms and relations in the framework of a "financial democracy" capable of forging increasingly close ties between the roles and institutions of the legal and economic systems operating in different countries.
Keywords: Tax law, Sociology, KOL research, Social justice, Financial democracy