European policy affects our lives: from air quality to the frequency of a bus service. Leiden researchers analyse how the European Union functions, how countries apply European policy and whether this policy actually provides solutions and delivers.

On 9 September 2020, Ruben de Graaff defended his thesis 'Concurrence in European Private Law'. The doctoral research was supervised by Prof. A.G. Castermans and Prof. S.C.G. Van den Bogaert.

How do crises produce changes in specific European Union foreign policy areas, and how should we conceptualise these policy changes?

In this article, Madeleine Hosli, Professor of International Relations at the Institute of Security and Global Affairs, and Jaroslaw Kantorowicz, Assistant Professor at the Institute of Security and Global affairs, discusses the relevance of structural variables in a time where European politics are…

This edited volume offers a critical discussion of the trade-offs between transparency and secrecy in the actual political practice of democratic states in Europe. As such, it answers to a growing need to systematically analyse the problem of secrecy in governance in this political and geographical…

Cristina Grasseni’s project

How do chemical contaminants traverse and affect terrestrial biodiversity and ecosystems?

This book is the first comparative study of estimative intelligence and strategic surprise in a European context, complementing and testing insights from previous studies centred on the United States. It does extensive empirical analysis of open-source material and interviews in relation to three cases…

On 7 September 2023 Didem Durak Akser successfully defended a doctoral thesis and graduated.

Grasseni's contribution to this special feature on food cultures, food systems, and agriculture in Europe builds upon her ongoing project Food citizens? Collective food procurement in European cities: solidarity and diversity, skills and scale.

The book addresses the question “How and why do people become involved in European homegrown jihadism?

The Master’s in European Union Studies at Leiden University offers students an opportunity to study the EU from multiple disciplinary perspectives.

The European union, where we live, work and study, is the most ambitious and powerful regional organization for international cooperation in the world. A mystery to many and derided by some, the EU has weathered intense geopolitical and economic storms over the last two decades. In doing so, it has…

Project leader Esther Kentin has published an article on the European chemical regulation REACH and the restriction of microplastics in a physics journal.

The European courtroom as political arena? Judicial interference in politically charged issues in European asylum law and criminal law

The Law of the European Union is a complete reference work on all aspects of the law of the European Union, including the institutional framework, the Internal Market, Economic and Monetary Union and external policy and action.

On 13 February, Professor Matthias Haentjens spoke at the conference “Proportionality in European Banking Regulation” at the Bank of Greece. This conference was organized by the Greek central bank, in cooperation with the University of Piraeus and the European Banking Institute (EBI).

European integration is under pressure. At the same time, the notion of a European administrative space is being explicitly voiced. But does a shared idea of the public servant exist in Europe?

Brexit has been a kind of shock therapy for the EU and has eventually led to more appreciation for European cooperation. That is what Professor Luuk van Middelaar claimed on 30 November at the conference ‘Brexit and the future of the European Union’ which marked the 60th anniversary of the Europa Institute…

The Team International Relations and European Studies addresses the interconnections and interdependence of contemporary global political, economic, security and culture from a multidisciplinary perspective rooted in the humanities. More specifically it is concerned with the study of international relations…

The annual excursion of the Adv. LLM programme in European and International Human Rights Law (EIHRL) took place from Sunday 16 to Saturday 21 April.

A look into the political history of collecting and the collections of Andean mummies in Western European museums from 1830-1930 through archaeology and paleoimaging.

Research on this theme concerns Europe’s position in global markets, its response to the emergence of new international trade and financial actors that challenge institutions where Europe has long had considerable influence.

How can groundbreaking research help Europe tackle the huge challenges it faces? At the launch of the Leiden Europe Hub, academics and policymakers discussed this in the heart of European democracy: the European Parliament.

On 20 June 2025, Melanie Fink presented her research on ‘Robo Swarms and Polygraphs: The Future of European Border Management and its Human Costs’ at the Research Workshop on ‘Migration law at the intersection of international, EU and domestic law: institutional structures and the protection of human…

How can we understand the implementation of EU policy and what challenges are involved?

The European Council and the European Commission have a similar role in agenda setting. Both place issues on the EU agenda. However, these institutions have distinct designs. They have different political attributes (the European Council has considerably more political authority) and information-processing…

The Centre for the History of European Integration (CHEI) is an initiative that brings together scholars working on European integration, broadly conceived, from a historical perspective.

What political factors affect the speed or duration of EU legislative decision-making?

Set up in 1991, this unique project aims to identify and describe the common lexical heritage of the most important Indo-European languages and language branches. The project has thus far resulted in twelve volumes published as The Leiden Indo-European Etymological Dictionary Series (Brill, Leiden).

The new project INFLANET will train young scientists in Europe to become experts in inflammation research. Professor Annemarie Meijer from the Institute of Biology Leiden coordinates the training.

International Relations and European Politics is one of the three organisational clusters of the Institute of Political Science.

EUROTYPES is a research project developed by political scientist Adina Akbik, for which she recently received a European Research Council Starting Grant. Her aim is to examine the impact of cultural stereotypes in European multi-level policy enforcement. One of EUROTYPES' innovations lies in its focus.…

Our Master Law in European and International Human Rights Law (LL.M.) looks at the various human rights protection mechanisms from a comparative perspective

Our research deals with the deep history of Europe and Eurasia, from the inception of farming up until the beginning of the Roman Period. This was a period in which key developments took place that had a profound impact on European landscapes and society until the present day. Our research and teaching…

Does a shared idea of the ‘public servant’ exist in Europe? Sager, Overeem, and others explore.

Leiden’s Institute for History has an exceptionally strong expertise in premodern European history in its global context, with specialists whose interests cover virtually the whole continent. We have a strong track record in leading larger research teams and work together with colleagues across Europe…

The project Advancing The European Multilingual Experience (AThEME) studied multilingualism in Europe by incorporating and combining linguistic, cognitive and sociological perspectives.

This paper develops a novel theoretical framework for the conduct of postmortems after major foreign policy surprises for the European Union and its member states.

This paper, written by Silvia D'Amato & Andrea Terlizzi, investigates the extent to which the European Union is strategically engaging against terrorism.

Akbik and Diessner expand the classic typology of police-patrol and fire-alarm oversight with two new categories: planning bureaus and ambulance chasers.

This paper explores whether multilateral surveillance and policy coordination under the ES was based on a path-changing or a path-dependent mechanism

European Law is a one-year Master’s specialisation at the internationally renowned Leiden Law School at Leiden University. The programme distinguishes itself by its broad intra-disciplinary approach, covering institutional, constitutional as well as internal market and competition law of the EU in addition…

This research concerns a network of labour law specialists in the EU. The growing internationalization of the economic market and the employment market has a major impact on legislation and research of labour law. Particularly within the European Union labour law is subject to constant development…

How to explain the apparent high success rates of the EU infringement procedures, which are the major tools for enforcing EU law, against the member states?

Alumni who live and work in Brussels met on 18 February at the annual Leiden Alumni in Brussels Event. As well as celebrating Leiden University’s 450th anniversary, they also looked at the challenges Europe faces.

How should European financial law best integrate considering the interaction of the relevant legal systems?

Leiden experts research ways in which European legislation is converted into national legislation. Knowing how this process works can inspire policy-makers trying to achieve their aims while abiding to Europan legislation.