Theory of Imperialism concerns the global systemic outcomes of the tendency for the rate of profit to fall in the capitalist system, and the objective impact of the consequences of those dynamics, and counter-tendencies in the world economy which are now generally associated with Marxian economics. As such it is often considered distinct and differentiated from the history of imperialism that extends through earlier historic periods and economic formations. J. A. Hobson's liberal critique of the emerging phenomenon has consistently been considered as seminal by all writers on the subject, and preceding and influencing Hilferding, Lenin "the principal English work on imperialism" and Luxemburg's early studies and formulations.
Samezō Kuruma in his 1929 Introduction to the Study of Crisis ends by noting "... my use of the term "theory of crisis" is not limited to the theory of economic crisis. This term naturally also encompasses the study of the necessity of imperialist world war as the explosion of the contradictions peculiar to modern capitalism. Imperialist world war itself is precisely crisis in its highest form. Thus, the theory of imperialism must be an extension of the theory of crisis."
Recent scholarship by Lucia Pradella amongst the archives of still unpublished manuscripts of Marx's studies of the world economy on his arrival in London corroborates those who have argued that, there was an immanent theory of imperialism in his writings. "Conceptualising society as coinciding with the state and the national territory, in fact, obfuscates the constitutive role of colonialism and imperialism, and leads to a naturalisation of the international inequalities resulting from capitalist development."