The human condition and its significance to International Relations have been in debate for centuries. Classical Realist thought has focused on the inherently aggressive and selfish nature of man and assumed that it is these qualities that ensure war and conflict are inevitable aspects of human society. Alternatively, neo-realism emphasises the system structure of international politics. R.J. McShea discusses the significance of the human nature tradition throughout the study of international relations. The endeavour to rid the world of the evil of war and the advancement of the conditions for peace have been developed from the assumption that the interaction of the states, and the way they ought to conduct relations among themselves, are dependent upon the nature of man. Thucydides' "History of the Peloponnesian War" is such a study of international relations. Not a philosophical work, it is considered of great importance within political and philosophical...