Targeted Killing in International Law is a book about the legality of targeted killing, written by Nils Melzer. It was first published by Oxford University Press in May 2008. The book explores the history of targeted killing, as a government strategy by multiple countries including the United States, the United Kingdom, Israel, Switzerland and Germany; for both military and law enforcement purposes. Melzer argues that directly after the September 11 attacks in the United States, perceptions of the tactic became more positive.

Melzer holds a PhD degree in law from the University of Zürich. His dissertation dealt with targeted killing and the book updates and revises that work. He had earlier written on the subject for Yearbook of International Humanitarian Law in 2006. Melzer serves as a legal advisor for the International Committee of the Red Cross (ICRC). He has lectured at the Master-level at the Geneva Academy of International Humanitarian Law and Human Rights.

The book received a favorable reception and was a joint winner of the 2009 Paul Guggenheim Prize in International Law given by the Geneva Graduate Institute. It garnered positive reviews in publications including the International Criminal Justice Review, the European Journal of International Law, the Leiden Journal of International Law, the Australian Year Book of International Law, the American Journal of International Law, and in the book Legislating the War on Terror: An Agenda for Reform.

Nils Melzer graduated summa cum laude from the University of Zürich with a PhD degree in law. Melzer worked for the District Court of Meilen, Zürich, first as a Judicial Clerk and then as Judicial Secretary. Melzer serves as a legal advisor for the International Committee of the Red Cross (ICRC). He lectured at the Master-level at the Geneva Academy of International Humanitarian Law and Human Rights.

Prior to the book, Melzer published "Targeted Killing or Less Harmful Means? – Israel's High Court Judgment on Targeted Killing and the Restrictive Function of Military Necessity" in the Yearbook of International Humanitarian Law in 2006, and a dissertation in 2007. Melzer also authored "Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law", published in 2009 by ICRC. Melzer's research was utilized in Section IX of the ICRC's Interpretive Guidance on the Notion of Direct Participation in Hostilities under International Humanitarian Law.

Targeted Killing in International Law is part of the series, Oxford Monographs in International Law. The hardback was first published by Oxford University Press on 29 May 2008, and subsequently in the United States by Oxford University Press, USA in July 2008. In January 2009, the work was published online at Oxford Scholarship Online. On 10 September 2009, Oxford University Press released a paperback in the UK. Oxford University Press, USA released a paperback on 9 November 2009.

Nils Melzer presents an historical, legal and moral examination of targeted killing. The author observes that after September 11, the Western world grew more supportive of targeted killing than ever before. The book recounts in depth how state-sanctioned targeted killing is perceived in other countries. He defines targeted killing as the premeditated selection of an individual person not yet in custody for elimination by force. Melzer analyzes all areas of the topic.

The book discusses related legal practices of countries including the United States, the United Kingdom, Israel, Switzerland and Germany. Israel was the first country to publicly acknowledge the practice—in November 2000. The author connects this policy initiative with Israel's ongoing conflict with Palestinian militants. Melzer argues that this policy was controversial—the issue came before the Israeli Supreme Court, where the matter was not decided for almost five years. The court's judgment was issued on 14 December 2006, but neither forbade nor endorsed the practice. Melzer asserts that it left multiple important legal conundra unresolved. Its significance was that it dealt not with a single incident, but rather with the nature of the policy itself and set forth conditions for examining the legality of future episodes.