Living with and being frustrated by the assessment practices of my high school and undergraduate teachers, which were based on written tests and carried out only at the end of the content, sparked my interest in investigating other forms of assessment. We found in formative assessment, an important theoretical framework for analyzing teacher practice, a perspective that makes it possible to look at the learning of each student, as well as the continuous learning of the teacher. Therefore, the book discusses my assessment practice during my supervision classes in a public school, observing my actions and trying to understand the assessment methodology used in the classroom.