This book offers the first comprehensive and analytically grounded study of Spanish defence policy from the democratic transition to the present era of renewed geopolitical competition. Spain has undergone a far-reaching process of military modernisation, professionalisation and multilateral integration, becoming an active contributor to NATO, the EU and international operations. Yet this transformation has remained uneven.

Bringing together leading specialists in strategic studies, political science, defence economics, civil-military relations and alliance politics, the volume examines how Spain defines, plans, funds and implements defence policy. It shows how external pressures, alliance commitments and European defence initiatives have been persistently filtered through domestic politics, fiscal constraints, public attitudes, industrial interests and historically embedded strategic traditions.

The book addresses key debates on NATO burden-sharing, European defence integration, the war in Ukraine, military readiness, procurement, industrial capacity and the relationship between national priorities and multilateral commitments. By combining theoretical insight with detailed empirical analysis, it fills a major gap in European defence studies and provides a new framework for understanding Spain’s defence trajectory as a case of uneven adaptation.

It will be essential reading for students and scholars of political science, international relations, security studies, defence studies and European studies, as well as for analysts, policymakers and practitioners interested in defence, strategy and international affairs.

Guillem Colom-Piella is an Associate Professor of Political Science at the Universidad Pablo de Olavide, Sevilla, Spain. He is currently on special leave as a senior advisor to the Spanish Chief of Defense Staff (EMAD), leading the area of geopolitical analysis. Colom-Piella is also an Associate Researcher at the Autonomous University of Chile, a member of NATO’s Innovation Hub, and a full member of the Academy of Military Sciences and Arts. He holds a PhD in International Security, a Master’s degree in International Relations, and degrees in Sociology and Political Science. His career includes roles in the Armed Forces Transformation Unit at EMAD, academic leadership positions, and teaching positions at various civilian and military institutions in Europe. He has published over 200 works on strategic studies, defense policies, and military innovation and has received multiple academic and military awards.