Frits Kalshoven is a retired professor of international law, and of international humanitarian law in particular (“Red Cross Chair”), of the University of Leiden. He currently is an adviser on international legal affairs to the Netherlands Red Cross Society. His publications include: Belligerent Reprisals, thesis, Leiden (1971); The Law of Warfare (1973); a series of articles on “Reaffirmation and Development of International Humanitarian Law Applicable in Armed Conflicts”, in Neth. YIL (1971-1978); “Arms, Armaments and International Law”, in the Hague Academy Recueil des Cours 1985-II; Constraints on the Waging of War (1987); Assisting the Victims of Armed Conflict and other disasters (ed., 1989); Implementation of International Humanitarian Law (ed. with Sandoz, Yves, 1989). In 1971, he received the Royal Shell Award for his work in the domain of humanitarian law and in 1973 the Ciardi Award of the International Society for Military Law and the Law of War for his thesis. The above text represents his farewell address delivered on 3 February 1989 in the University of Leiden.