An introduction to and analysis of diplomatic theory, defined as systematic reflection on diplomatic ideas, activities and issues. Such reflection has historical, conceptual and normative elements that by nature pertain to diplomatic practice as empirical referent. This involves the critical examination of key assumptions on diplomacy. On the one hand, since diplomatic ideas inevitably reflect broader international relations theories and since the modern diplomat should have some understanding of the latter, attention is given to these. On the other hand, on a capita selecta basis, attention is paid to theoretical perspectives on issues that appear on the global diplomatic agenda.