Printed between 1910 and 1919, the Diccionario biografico obrero de Chile was the first book of its kind produced in Latin America in the twentieth century. Coordinated by journalist Osvaldo Lopez, this dictionary sought to show the trajectories of leaders and representatives of the Chilean labor world to the beginning of the century. Although this work has served as a source for many investigations, little is known about its production process, and even less about their general contents, and what they indicate about the labor elites, their self-images, objectives or print culture. Therefore, this paper seeks to contribute to the analysis of this collective biography, by rebuilding its publishing history and examining the key feature which identified the workers: sociability.