This book offers a pioneering examination of how the Brazilian legal system is evolving to protect vulnerable populations amid growing social inequalities and judicial transformation. It introduces the concept of the Procedural Microsystem for the Protection of the Vulnerable, a procedural micro-system recognized by Brazil’s Superior Court of Justice (STJ), and explores its implications for constitutional and institutional realignment within the justice system.

Focusing on two key autonomous institutions, the Ministério Público (Public Prosecutor’s Office) and the Defensoria Pública (Public Defender’s Office), this book analyzes their roles in promoting access to justice and safeguarding fundamental rights. Through a detailed study of legal frameworks, jurisprudence, and institutional practices, it investigates how these bodies support structurally and socially vulnerable groups, including children, the elderly, women, racial minorities, people with disabilities, and Indigenous communities.

Combining theoretical insight with practical relevance, this book introduces innovative concepts such as procedural constitutionalization, functional complementarity, and decolonial due process of law. It also draws on comparative legal experiences, particularly from Latin America, to situate its analysis within broader debates on legal pluralism, inclusive development, and human rights.

Essential reading for legal scholars, judges, prosecutors, public defenders, and policymakers, this book is especially relevant for those researching procedural law, constitutional law, institutional performance, and the protection of vulnerable populations in the Global South.

Hermes Zaneti Junior holds a Ph.D. in Law from Universidade Federal do Rio Grande do Sul (2005) and from Università degli Studi di Roma Tre (2014), with a postdoctoral fellowship at Università degli Studi di Torino (2014). He also holds a Master’s degree in Law from UFRGS (2000) and a Bachelor’s degree in Legal and Social Sciences from Universidade do Vale do Rio dos Sinos (1997). He is a full professor at the Federal University of Espírito Santo (UFES), a Prosecutor at the Public Prosecutor’s Office of Espírito Santo (MPES), and an active member of several academic and scientific institutions, including the Brazilian Institute of Procedural Law (IBDP), the Ibero-American Institute of Procedural Law (IIDP), and a former member of a global research program on civil procedure in the Max Planck Institute. His academic work centers on civil procedure, collective litigation, legal precedents, and structural justice. He has authored and co-authored over 60 books and hundreds of articles, with notable works such as Curso de Direito Processual Civil, Processo Coletivo: modelo brasileiro, and Casebook de Precedentes Judiciais, establishing himself as a national and international authority in the field.

Maurilio Casas Maia holds a Ph.D. in Constitutional Law from Universidade de Fortaleza (2020), a Master’s degree in Legal Sciences from Universidade Federal da Paraíba (2011), a Bachelor of Laws from Universidade Nilton Lins (2006), and has completed three postdoctoral programs in Law at Universidade La Salle (2023), Universidade Federal do Espírito Santo (2024) and Università del Salento (Italy, 2025). He is affiliated with the Federal University of Amazonas (UFAM), the Public Defender’s Office of the State of Amazonas (DPE-AM), and the Brazilian Association of Procedural Law (ABDPro). As a Public Defender and permanent faculty member of the UFAM Graduate Program in Law, his work focuses on the protection of vulnerable groups, access to justice, and procedural constitutionalism. He has authored dozens of scholarly articles and book chapters and has organized or co-organized more than 30 volumes, including Defensoria Pública e a Defesa Constitucional de Grupos Vulneráveis and Dano Temporal: o valor jurídico do tempo.