The Importance of Interdisciplinary Research and Teaching -- The Needs of Interdisciplinary Research -- The Nature of KOSs to Serve Interdisciplinarity -- Phenomenon versus Discipline-Based Classifications -- The Feasibility of Developing Such a KOS -- Domain-Oriented Interdisciplinarity -- How to Develop a KOS to Serve Interdisciplinarity -- Benefits of a Comprehensive Phenomenon-based Classification -- Responding to Potential Theoretical Critiques -- Concluding Remarks and the Next Steps. .