A companion volume to the author's seminal textbook War, Aggression and Self-Defence, Third Edition, Cambridge (2001), this book focuses on issues arising in the course of hostilities between States, with an emphasis on the most recent conflicts in Iraq and Afghanistan. The main themes considered by Yoram Dinstein are lawful and unlawful combatants, war crimes, including command responsibility and defences, prohibited weapons, the distinction between combatants and civilians, legitimate military objectives, and the protection of the environment and cultural property. Numerous specific topics that have attracted much interest in recent hostilities are addressed, such as human shields, feigned surrenders, collateral damage and proportionality, belligerent reprisals and weapons of mass destruction.