This article contains a contextualized translation of the first part of the diary written by Fr. Martín Gusinde SVD, a German missionary and ethnographer, during his third trip to Tierra del Fuego (1921-1922). As such, it forms a part of the series of previous publications concerning this topic. The original version of the diary is preserved in the archive of the Anthropos Institute in Sankt Augustin, Germany. In the article, I analize the background and circumstances of Gusinde’s research during the third trip to the region that was conducted in the company of another SVD missionary and ethnographer, Wilhelm Koppers.