This chapter outlines the book’s overall argument and structure, and explains its methodology. The overall argument is that teachings generally have low weight in the ICJ, but this varies by work and between judges, and that it is to some extent possible to explain or predict those variations. The structure follows the overall argument, with a chapter on teachings in the ICJ generally, one on variations between works, and one on variations between judges, following an introduction and a general chapter on the ICJ Statute 38(1), and followed by concluding reflections. The methodology consists of a traditional legal analysis, an empirical analysis, and interviews.