This volume develops outlines of a general theory of subject didactics. The authors refer to it as general subject didactics and understand it as a metatheory of subject didactics. In this framework, the relationship between subject-specificity, subject-related educational theory, and empirical as well as theoretical subject didactic research is systematically reflected upon concerning subject-specific learning both inside and outside of school. In doing so, general subject didactics captures and explains the subject didactics in their similarities as well as in their differences. The sequence of chapters follows an internal logic: The first section outlines the development of subject didactics and its particular status in the tension between educational sciences and subject sciences. The second section addresses the similarities and differences of the individual subject didactics with regard to learning.