This book, the result of a master's thesis defended at the Postgraduate Programme in Collective Health at the Federal University of Mato Grosso in 2009, is about the work of the Community Health Agent (ACS) in the municipality of Sorriso, located in the northern region of the state of Mato Grosso. An analysis was made of the work of CHAs based on their competences and skills as described by the Ministry of Health, taking into account municipal management and the work of other team members. Sorriso, at the time of the study, had almost the entire population covered by CHWs (88%), making it a state reference and one of the reasons for choosing it for the case analysis. Even ten years after the data was collected, the research is still relevant because it allows us to reflect on the nuances of this professional, a member of the family health team, a strategy that is still emerging on the national scene.