Luard is mainly known for his extensive writings on numerous aspects of international relations. He is also known for his sociological theories including the hierarchy theory. His exhaustive study of war,
War in International Society: A Study in International Sociology, was published in Britain in 1986 and by Yale University Press in the United States in 1987. Luard also contributed a number of studies in support of "community socialism" in Britain, most notably
Socialism without the State (1979). An account of his life and work appeared in the
Oxford Dictionary of National Biography in 2004. ==References==