Summary Louis Hjelmslev's theory of participative correlations is a quite dense and far-reaching version of the so-called "markedness theory", by which structural linguists like Roman Jakobson and Nicolaj Troubetzkoy intended to describe some odd linguistic phenomena in grammar and phonology. Jakobson's and Troubetzkoy's originally idea was further developed, flowing into American linguistics and becoming progressively more shared (and criticized). Louis Hjelmslev's model had not this fortune. My book reconstructs how Hjelmslev conceived and elaborated his own theory, tapping the entirety of his production as well as unpublished sources and correspondence. Because of dealing with such neglected topic and in this way, my book is a one-of-a-kind work in linguistic and epistemological research. SSR A publication - in this case: a monography - is in itself an interface with the public. Although the book represents the output of a very specific and theoretically dense research on an often neglected source of language science, thus of no straight accessibility for the vast public, it still constitutes a milestone by itself not just for the topic but also because it couples philological attention and theoretical discussion, placing the output within the larger framework of the publicly available digital database of "Infrastructuralism" concerning the unpublished documents of Danish structural linguists, funded by the Carlberg Foundation.