This book examines the interactions between trade policy and foreign and security policy in EU external action as a nexus of practices. Drawing on the rich empirical material of over 50 in-depth interviews with EU officials, members of the European Parliament and member state diplomats, the book reconstructs and analyses the distinctive institutional cultures of the Directorate-General for Trade and the European External Action Service, their policy practices and the effect on EU external action. It appeals to scholars of political science and international relations.