This study focuses on the work 'A Ilha de S?o Tom?' by Francisco Tenreiro (1921-1963). Francisco Tenreiro, a graduate of the Escola Superior Colonial and a member of the Center for Geographical Studies at the University of Lisbon, wrote a geographical study of the largest island in the archipelago of S?o Tom? and Pr?ncipe as his doctoral thesis in Geography. His work was analyzed based on the geographical coding of the scientific narrative and the subsequent thematic recoding of the cartography generated. The main purpose of this study is to highlight the reciprocal influence of the scale of scientific analysis and elements of the author's identity. It is concluded that the work reveals an author with various scales of 'scientific identity'. From this point of view, we can say that Francisco Tenreiro is, at the same time, or alternately, in an identification not always free of hesitations, ambiguities and even strong intimate tensions - a 'colonial/ultramarine officer', a 'European geographer' and a 'humanist from S?o Tom?'. Keywords: S?o Tom? and Pr?ncipe, History of Geography, Tropical Geography, Francisco Tenreiro.