Foreign relations law and public international law are two closely related academic fields that tend to speak past each other. As this innovative volume shows, the two are closely interrelated and depend on each other for their mutual construction and identity. A better understanding of this relationship is of vital importance for upholding important constitutional values like democracy, the rule of law and the protection of human rights, while enabling states to engage in meaningful forms of international cooperation. The book takes a close look at the encounters between the two fields and offers perspectives for a constructive engagement between the two. Collectively, the contributions argue that the delimitation between the two fields occurs in a hybrid zone of interaction which requires both bridges and boundaries: bridges for the construction of the relationship between the two fields, and boundaries for preserving key normative expectations of both domestic and international law. This title is also available as Open Access on Cambridge Core.