This book features a discussion on the modernisation of law and legal change, focusing on the key concepts of "innovation" and "transition". These concepts both appear to be relevant and poorly defined in contemporary legal science. A critical reflection on the heuristic value of these categories seems appropriate, particularly considering their dyadic value. While innovation is increasingly appearing in the present day as being the category in which one looks at the modernisation of law, the concept of transition also seems to be the privileged place of occurrence for such dynamics. This group of Italian and Brazilian scholars contributing to this volume intends to investigate such problems through an interdisciplinary prism. It includes points of view both internal to legal studies - such as the history of law, theory of law, constitutional law, private law and commercial law - and external, such as political philosophy and history of justice and political institutions.