The author emphasizes Hobson’s doctrine of imperialism and the related theory of under-consumption for which he is best known, while arguing that the lesser known of Hobson’s doctrines—which the author describes as the ‘organic theory of surplus value’—is essential to a full appreciation of the coherence of Hobson’s thought. Allett compares the analyses of Hobson, Adam Smith, J.S. Smith, the Webbs, T.H. Green, Bosanquet, Marx, Lenin, Keynes, and Hobson’s comrade-in-arms L.T. Hobhouse and puts in perspective the dismissive critiques of those contemporary scholars who claimed that Hobson’s work is value-laden, simplistic, and contradictory. This study presents an integral analysis of the life, times, and thought of a profound and original thinker, whose legacy to social democratic thought has yet to be fully appreciated.