The Gates of the Sea examines the paradoxes of maritime search and rescue at Europe's frontier. Focusing on Spain, Luna Vives explores how governments have redefined maritime rescue systems towards border control. Unlike other European countries, Spain chose not to assign this responsibility to a militarized state security force, but to a civilian agency whose workers often liken themselves to firefighters of the sea: they are dedicated to saving lives, not enforcing borders. Caught between their duty to protect life at sea and government efforts to transform them into border enforcers, rescuers have pushed back, primarily through their anarcho-syndicalist union, the CGT. Committed to border abolition and international solidarity, the rescuers' struggle positions them within a global movement of resistance to the politics of organized abandonment along the external borders of the European Union. Vives' revelatory, deeply researched and accessible book grapples with both state methods of control and containment and, crucially, ways in which solidarity activism can thrive in unexpected places.