For those delving into international law, several books stand out as essential reading. "The Law of Nations" by Emer de Vattel remains a classic, offering foundational insights into the principles governing state behavior. Vattel's work is a cornerstone for understanding the rights and duties of nations.

Philip Jessup's "Transnational Law" explores the complexities of legal interactions across borders, highlighting the interplay between domestic and international legal systems. This book is crucial for grasping the fluid nature of modern legal challenges.

"International Law" by Malcolm Shaw provides a comprehensive overview, covering everything from state sovereignty to human rights. Shaw's clear explanations make this a valuable resource for both students and practitioners.

For a critical perspective, "The Gentle Civilizer of Nations" by Martti Koskenniemi examines the evolution of international law through a historical lens, challenging readers to consider the political and social contexts that shape legal norms.

Lastly, "The Internationalists" by Oona A. Hathaway and Scott J. Shapiro offers a compelling narrative on how a group of legal thinkers transformed the world order, advocating for peace over war. Their storytelling brings to life the transformative power of international law.

These books provide a solid foundation for understanding the complexities and nuances of international law, each offering unique insights into its development and application.