The purpose of this article is to establish that Lewis Mumford’s historical and philosophical writings were heavily influenced by the psychoanalytic theories of Sigmund Freud. It is argued that Freudian ideas and concepts played a foundational role in the construction of Mumford’s views on the nature and function of mind, culture and history, which in turn founded his views on the relationship between technology and society. Indeed, it is argued that a full understanding of Mumford’s technological writings cannot be achieved (...) until one has grasped their psychoanalytic influence. To this end, this article will reconstruct the psychological views of Lewis Mumford and indicate how they draw upon and modify Freudian theory. It will then be shown how Mumford’s theory of the psyche interacts with Mumford’s own concept of the idolum. This interaction, I will argue, considerably underpins Mumford’s holistic views on the relationship between society and the individual and between the internal and external world and will require us to reconsider our understanding of Mumford’s philosophy of technology, particularly with regard to his descriptions of monotechnics and biotechnics, the authoritarian and democratic technological forms. It will be argued that for Mumford the division intechnics corresponds to a division in the human psyche, and indeed arises from it. Not only will an appreciation of Mumford’s Freudian influence alter our understanding of Mumford’s technological writings in general, but also in particular it can enable us better to comprehend the reasoning behind Mumford’s recommended method of resistance to the modern power complex of the megamachine. Such a revised understanding of Mumford’s philosophy also undercuts any attempts to characterize his position as being a technological determinist one. Rather, his philosophy of technology is better understood as a form of technological voluntarism. (shrink)