This book explores the concepts of ratio decidendi and obiter dictum from a historical-comparative perspective. It provides a comprehensive review of legal doctrine on precedent, delving into English and American Law so to illustrate its applicability to the Brazilian legal system. How we deal with precedents is its main topic.

Definitions within legal fields have always been subject to significant debate, with some recurring more often than others. Every now and then, a perspective arises which transforms the orthodoxy. As such is the case with the notion of precedent. Outlining its contours establishes a continuity between disparate and temporally distinct traditions. It requires theoretical-philosophical speculation, historical-comparative sense, and attention to the particularities of Brazilian Law.

This book includes in-depth discussions of the development of the various understandings of the ratio, outlines the notions of ratio decidendi and obiter dictum, and illustrates its application within legal practice. It suggests an understating of the ratio capable of dealing with identical, similar and distinct issues in the Brazilian legal system. Following an extensive debate on the characterisation of the ratio, it explores the notion of obiter dictum, its definition, abilities and effects. 

The target audience of this book includes researchers, scholars and practitioners, especially those interested in the practice of precedent from a perspective that intertwines legal theory, legal history and comparative law.