Vida e Morte de M.J. Gonzaga de Sá, Lima Barreto's novel, in form of memorois, exposes the critical and pessimistic reflections of a man in his sixties, Gonzaga de Sá, about social and political transformations caused by formation of Brazilian Republic and hypocritical cultural patterns of Rio's bourgeoisie. This book, written between 1907 and 1908, was published by Monteiro Lobato's Revista do brasil in 1919. Dialogues and editoral interventions in the book can be traced from 42 letters between author and editor. These letters novel's original writings and other documents were read in order to understand in which cultural, literary and editorial conditions Vida e Morte de M.J. Gonzaga de Sá was published. In this perspective, we intended to develop a critical and sociological study, recording and analysing: interventions and choices during the editorial mediation process, participation of different actors involved with editorial scenery, prodution circumstances, cultural expectations, publishing and distribution strategies, as well as reception and critical fortune about the novel. These analyses allowed us to understand tha if, on the one hand, for Monteiro Lobato, Gonzaga de Sá was an editoral and marketing failure, on the other hand, for Lima Barreto, the novel resulted in critical praises and honorable mention award at Academia Brasileira de Letras. Therefore, in order of proceed for this research, the theoretical-methodological references are: philological tradition, that covers the study of textual process; Jerome McGann and Don Francis McKenzie's Sociology of texts, which emphasizes prodution, circulation and reception processes; and Roger Chartier's purposes about cultural and editorial mediation.