From the first paragraph of the book review:

Christian Henderson’s volume on The Use of Force and International Law [NEW YORK: CAMBRIDGE UNIVERSITY PRESS, 2018. PP. XI, 428. INDEX] is a comprehensive exposition of the international legal regime governing recourse to force–jus ad bellum. Henderson, who is a professor of international law at the University of Sussex and co-editor of the Journal on the Use of Force and International Law, demonstrates comprehensive mastery of the subject throughout. The Use of Force and International Law, in the tradition of distinguished volumes like Ian Brownlie’s International Law and the Use of Force by States, Yoram Dinstein’s War, Aggression and Self-Defence, and Christine Gray’s International Law and the Use of Force, embraces an “objective positivist” (p. 4) approach in an effort to describe and explicate the substantive content–the lex lata–of the law on the use of force. The volume does not present Henderson’s preferred view of the law or advance a normative call for the development of jus ad bellum in a particular direction. That said, the law governing the use of force is characterized by many contentious claims and disagreements, which makes it a challenge to simply say what the law is. Henderson’s book presents the competing views on many of these issues in a thoughtful, balanced, and scholarly manner, which makes the book highly suitable for use in teaching an advanced level course. As a whole, this is a deeply researched, comprehensive, and erudite contribution to the literature on the law governing recourse to force.