By launching, in 1936, Machado de Assis - a critical and biographical study, Lucia Miguel Pereira would consecrate herself as a biographer, critic and historian of Brazilian literature. Still considered today as a reference reading about Machado, the work embarks on a psychological, social and cultural interpretation of the life and work of the writer. Such a critical bias, which is supported by biographical and extraliterary references, would come to be despised by the main readings about Machado from the 1960s onwards by an academic literary criticism immersed in Structuralism and interested mainly in Machado's text itself. However, 80 years after the release of Lucia's book, Silviano Santiago would resume both the author's psychosocial interpretation and the reading of Augusto Meyer's "spectator of himself", in the hybrid of novel and essay Machado (2016). This article aims to investigate the relevance of the critical biography of Lucia Miguel Pereira, as well as to discuss the relevance of the use of biographical data in the reading of Machado's texts in contemporary times.