This article analyses the role of piracy in the Chilean publishing industry, starting with the copyright dispute between the Sur publishing house and Editorial Ercilla between 1936 and 1938. Through publications in magazines, analysis of catalogues and correspondence between writers and editors, the implications for the book market of the negotiations, translations and publications of titles without the due permission of their authors are examined. The hypothesis is that piracy was a central practice in the development of Chilean publishing houses, as it allowed for an increase in the resources of the companies, as well as an expansion of the market in terms of supply. The text advances along three lines of analysis: first, it develops a conceptualisation of piracy as a key reading in the historiography of the book. Second, it examines its presence and impact on the Chilean cultural market and legislation. Thirdly, the professionalisation of Ercilla as a representative of literary diffusion is analysed.