Guest Post: The Tallinn Manual

Why Matter Matters

by Nina Krijnen


The “Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations” is a legal manual, which –as the title gives away- tells the reader how international law applies to cyber in 154 ‘black letter rules’. I was fascinated by the Manual as it appeared to me as so much more than a book. This made me think about what the Manual is, and more importantly, what is does. In my thesis I consider the Manual as an actor and research how it manifests itself.

Following this line of thought, I looked into the study of objects. Yet this approach – to study ‘things’ – is rather new to the field of international law. Building instead on scholarship in international relations, anthropology, and political geography, I created a framework to study the manifestation of the Tallinn Manual in the Netherlands. I visited libraries, ministries, and a large international Cyber Seminar to understand how the Manual manifested itself. I took pictures, participated in a conference, and interviewed people.

I have been surprised by how much I could find out about this one object by simply studying what it did in certain places, why it was there, and who decided for it to be there. I found that the Tallinn Manual was not simply a book. It was a political artefact that acted differently in different places. At the Ministry of Foreign Affairs and at the Ministry of Defence, the Manual acted as a prize in a ‘locked shields cyber defence exercise’, a tool to check primary sources, and as a means to advance foreign policy on cyber. At libraries, the Manual pointed towards access, scarcity, and circulation. At the Cyber Seminar, I found that the Manual created links between groups and differentiated between ‘us’ (those in favour of the Manual) and ‘them’ (those disagreeing with the Manual).

My research demonstrates that objects, although largely neglected in legal scholarship, are relevant for the study of international law. We have to look closer at the role of objects, their different manifestations, and their different meanings to understand practices in the field of law and the politics behind it. In other words, matter matters to our understanding of international law.



Nina Krijnen, Materiality matters: A study on the manifestation of Tallinn Manual 2.0 on the International Law Applicable to Cyber Operations (master thesis, Vrije Universiteit Amterdam, 2018).

Interested in reading this thesis? Contact us at



The Tallinn Manual in the handbag of the legal officer at the Dutch Ministry of
Foreign Affairs.


The Tallinn Manual (at the top) at the office of the legal adviser at the Cyber
Command of the Dutch Ministry of Defence.


Defensie_Inside Manual
Text on the inside of Tallinn Manual 2.0 written by the judges of the legal team at
the 2017 Locked Shields cyber defence exercise organized by NATO.
Peace Palace Library_Inside TM
Tallinn Manual at the Peace Palace Library after requesting it at the librarian’s
reception desk.
Library Leiden University
The bookcase of the International Institute of Air and Space Law at the law
library of Leiden University where the Tallinn Manual can be found.
Cyber Seminar_Manual
A copy of the Tallinn Manual in front of Professor Terry Gill’s seat, one of the
panellists in the second panel and member of the International Group of Experts of both
Tallinn Manual 1.0 and 2.0.
Cyber Seminar_Twitter pictures Lisa Past
This picture was featured on the Twitter page of Liisa Past, Chief Research
Officer at the Cyber Security Branch of Estonia’s State Information Agency. It shows Tallinn
Manual ‘birthday cakes’ at the Cyber Seminar. The image on the cake is taken from the
cover of the actual Tallinn Manual.



Nina Krijnen is legal sightseeing correspondent in New York. She is also Senior Research Associate at the Public International Law and Policy Group (PILPG). She is currently living in New York for her internship position as Advisor to the Permanent Mission of the Kingdom of the Netherlands to the United Nations. Nina is a recent Law and Politics of International Security (LL.M.) graduate from Vrije Universiteit Amsterdam and is pursuing her MSc in Crisis and Security Management at Leiden University.

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