This is a thoroughly revised and updated edition of a book originally published in 2004. In the stretch of time since the first edition came out, interest in the law applicable in the conduct of hostilities in international (as well as non-international) armed conflicts has grown apace, and there has been a veritable spate of new books, articles and studies relating to diverse dimensions of this branch of international law. Even more significantly, the case law – especially, but not exclusively, that of the International Criminal Tribunal for the Former Yugoslavia – has become more abundant. There are also new texts: not only treaty texts but also restatements of the law.

While the main contours and theses of the first edition have been retained, countless changes have been introduced in the book to reflect new developments, address issues not fully explored before, and – based on lessons learned from actual teaching and training in a number of countries – add useful definitions and explanations. There are some new substantive sections (preeminently, direct participation in hostilities and ‘human shields’). Others have been considerably augmented.

To complement the changes in the text, the table of contents has been expanded. The new edition also has an easier cross-referencing system, to enable a closer look at the way in which similar rules mesh in different contexts. The numerical cross-references are to paragraphs and not to pages.

To facilitate syntax, generic pronouns relating to individual combatants or civilians are usually drawn in masculine form. This must not be viewed as gender specific.