In French contemporary literature and culture the imaginary („l’imaginaire“) is a widespread and quite popular notion which is nowadays frequently used in various contexts (academic and non-academic), whereas in Germany the term and the concept it designates seem to be more or less restricted to the scholarly discourse. In the German humanities the imaginary („das Imaginäre“) has become a key notion of interdisciplinary research and is thus regarded as a ‘terminus technicus’. In France, by contrast, the term l’imaginaire has been discovered and explored by poets and critics as well as philosophers and mathematicians since the early nineteenth century. In the first half of the twentieth century it is employed by modernist poets and artists of the avant-garde and cherished as a crucial concept in so far as it seems to offer a possible link between the individual poetic invention and its social or political dimension. Theories of the imaginary like the one developed by Cornelius Castoriadis thus participate in a wider academic and poetological discussion. The following essay focuses on the question how the reciprocal relationship between the individual and social components of imaginative activity is conceived of before Castoriadis’ seminal study, and how his key notions differ from earlier concepts of the imaginary. The originality and innovative quality of Castoriadis’ oeuvre (which are beyond questioning) can better be assessed and appreciated when compared to its predecessors and the stimulating discursive formation it responds to.