The Degrowth Manual is one of the tools used at the Degrowth Institute, an initiative whose aim is to establish emancipatory narratives in cities whose populations have been steadily decreasing in recent years. Our mission is to challenge the notion that suggests that growth - population in particular - is necessary when determining the (present, and future) success of a human settlement. Our objective is to do so by establishing bottom-up, transversal, and horizontal approaches to master-planning in these territories. We base our work on researching, working with and in, shrinking cities, and proposing strategies for addressing challenges that emerge, such as how to work with industrial heritage, vacancy, or shifting job markets, among others.