There are no identical federalisms or a general model that works as a reference or starting point. Federal countries have histories, trajectories, discontinuities, institutions and processes that make them unique and unrepeatable experiences. Comparisons can help us in different ways. They can enable us to more clearly prevent the consequences of adopting specific agreements. Through the identification of similarities and differences, we can think over certain aspects of the agreements adopted, and its circumstances that might otherwise go unnoticed. Furthermore, comparisons can suggest positive and negative lessons; we can learn not only from the successes, but also from the failures of other federations and the mechanisms and procedures they have used to deal with problems. The idea of comparison, then, consists of a constant attempt to generalize, decompose, disaggregate and re-spin the significant points of these trajectories that may represent an institutional strength or a coordination experience worthy of being studied and, with particularities, assimilated in other contexts. “Models to build: current federal processes, decentralization of power, and challenges of multilevel government” is a collective work in terms of its size, which has required two years of collaborative work by social scientists from five continents and almost twenty universities, gather together in the challenge of thinking of federalism as a preferred tool for state management in the 21st century. We hope that this proposal will serve as a reference for future studies on the subject and as an input for the management of political institutions, university teaching, scientific analysis and the dissemination of a current topic and centrally in the agendas of the main Law professorships and Political Science of the planet.