This book follows the history of the international law of peace and armed conflict over the last 25 years. It highlights both parameters that have remained the same during this time as well as new challenges that this field of international law faces today. The idea for this book was born at the international conference ‘From Cold War to Cyber War’, held in Bochum on 14–15 November 2013. The conference celebrated the 150 years anniversary of the Red Cross, the 25 years anniversary of the Institute for International Law of Peace and Armed Conflict (IFHV) and also the 20 years anniversary of the Network on Humanitarian Action (NOHA). The conference was so rich in inspiring contributions from both academics and practitioners that organisers and participants decided to combine the results of the conference into an edited book collection on the recent evolvement of the international law of peace and armed conflict—the result of which you hold now in your hand.