Over 2 billion people (61% of the world's employed population) work in the informal economy. Due to its pervasiveness, informality plays a major role in understanding a wide swath of ideas, such as development, work, employment, governance, and growth. Its scope, nonetheless, goes far beyond economic definitions and political agendas. As the book argues, at the root of informality lies another comprehensive, yet generally unnoticed-or at best improperly treated-phenomenon: that of noncompliance with the law. Whilst it is true that much attention has been paid to the economic aspect over the past 5 decades, the same cannot be said about the legal aspect, which is one of its constitutive features. This book takes the first steps in this direction. The book provides an account of the phenomenon's legal nature through the lens of a case study on street vendors in Brazil, focusing on what can be conceived as noncompliance and by which forms noncompliant behaviour can be assessed. It goes on to set out the most striking impacts of noncompliance; specifically, what happens with the legal system when noncompliance becomes pervasive.The Nature and Impacts of Noncompliance was awarded The European Award for Legal Theory 2022 from the European Academy of Legal Theory (EALT), Prêmio Abrafi de Teses 2022 from the Brazilian Association for Philosophy of Law and Sociology of Law (Abrafi), and the 2024 RCSL-ISA Adam Podgórecki Prize.