This text serves as a comprehensive, foundational treatise designed to explain the core principles and systemic structure of public international law. Authored originally by Ian Brownlie and maintained by James R. Crawford, the work synthesizes decades of legal precedent, treaty law, and state practice. It provides a structured framework for understanding how international legal norms are created, applied, and enforced within the global community.

Legal scholars and practitioners widely regard this text as a definitive reference for both students and professionals in the field. Readers frequently note the academic density of the prose, which is balanced by its rigorous and systematic approach to complex legal doctrines.