This study offers a comprehensive analysis of utilitas, a central concept in Roman law, and its pivotal role in shaping legal interpretation. Moving beyond its traditional view as a merely pragmatic tool, utilitas is shown to guide legal outcomes that not only address practical needs but also align with broader ethical values of righteousness and justice. It argues that a complete understanding of utilitas in legal reasoning – both in meaning and function – can only be achieved by synthesizing jurisprudential, philosophical, and rhetorical perspectives. Through this interdisciplinary lens the e-book demonstrates that decisions made utilitatis causa, exceptional in their departure from established legal rules, can only be fully understood through the lens of rhetorical theory of legal interpretation, offering a framework that transcends the limitations of literal interpretation. Contributing to ongoing scholarly discourse in Roman law, legal theory, and philosophy, this study provides fresh insights into a concept that remains central to contemporary discussions of legal interpretation and justice.