The unifying theme of the book is the imperfect nature of the cosmopolitan approaches and schemes of selected writers in early modern European history. It challenges the widespread assumption that the eighteenth century was a cosmopolitan century, and argues that many writers labelled as 'cosmopolitans' turn out to be half-way cosmopolitans at best, writers focussing on European society (rather than their own home countries), or endorsing a form of cosmopolitanism very different from contemporary notions. Individual chapters analyse the cosmopolitan dimension of the so-called 'classical' writers of the law of nations like Vitoria, Wolff or Vattel and their role as possible accomplices of European colonialism and exploitation, the pan-European or cosmopolitan plans of some British authors, the economic, indirect and weak cosmopolitanism of more mainstream authors like Hume or Smith, and late eighteenth-century international legal theory and its gradual move towards a state-centred approach. The idea of a universal natural law was compatible with a hierarchy of races in the past. Moral or human rights cosmopolitanism was often imperfect, half-hearted, or half-baked, though the book argues that we should be lenient with these early attempts. Forms of indirect, long-term economic cosmopolitanism usually triumphed over its contractual version. One chapter offers an interpretation of a passage in Kant's Perpetual Peace, where he characterized the natural lawyers Grotius, Pufendorf und Vattel as "miserable comforters", and an exposition of his criticism of their international theories from a cosmopolitan perspective.