In defense of sources in uncertain times As the new associate editors of História, Ciências, Saúde-Manguinhos (HCSM), we would like to invite you to contribute to the "Sources" section. Identifying and disseminating research sources has a meaning that extends beyond mere documentary description. It involves contextualizing and criticizing documents in multiple formats, pointing out the limits and the potential for utilizing them in the field of historical research; beyond this, it means implementing a radical historicization (Oliveira, 2007) that can make up for the power games that influenced their production, circulation, and institutionalization. As most historians know, critical analysis of a document or set of documents is a prerequisite for good historical research. The sources not only provide evidence for interpretation by historians, acting as a condition for validation, but also describe pathways, indicate agency, and allow comparisons. At a time when open science is being discussed, the study and dissemination of sources is gaining new momentum for providing greater visibility and transparency to research and enhancing dialog between peers. In fact, the establishment of history as a discipline was born out of rigorous methods for critiquing sources. This can be seen in the roadmap of topics discussed in nineteenthcentury manuals which established history as the science of knowing the past. Although many subsequent reflections have denounced the positivism underlying the early days of the discipline, and it was also strongly affected during the second half of the twentieth century by critiques of rationalism applied to interpreting social phenomena and very authority of the historical text, recent decades have been characterized by a "return" to the sources which avails itself of archival criticism and its place in constituting "cultures of knowledge" (Head, set. 2010), an especially powerful perspective in the field of decolonial studies. From this same vein emerge studies that focus on archives and collections as objects of study rather than mere sources of historical knowledge, investing in their connections with the fields of memory and identities (Burton, 2005). Today, returning to the sources takes on new meaning. Amid the spread of openly distorted discourse on the past, including conservative negation and revisionism which propagate online, the historical sources emerge as a guarantee, along with the procedures that ensure their veracity. As one of the main figures in the movement to return to the sources says: "The historian does not require people to believe him, under the pretext that he is a professional knowledgeable in his field …, but rather offers the reader opportunity to verify his information" (Prost, 2008, p.55).