"De Jure Naturae et Gentium," written by Hugo Grotius in 1625, is a foundational text in international law and natural law theory. The title translates to "On the Law of Nature and of Nations," and it explores the principles governing human conduct and the relationships between states. Grotius argues that certain laws are inherent to human nature and can be understood through reason, independent of divine command. The work is significant for establishing the idea that nations are bound by a common set of moral principles, which laid the groundwork for modern concepts of sovereignty and international relations. Grotius emphasizes the importance of treaties and agreements, asserting that mutual respect among nations is essential for peace and cooperation.