The book anwsers the question under what circumstances a trial during the times of an armed conflict can be considered a war crime under Article 8 of the Rome Statute of the International Criminal Court. The author's work starts with the account of the historical judgements made on the topic. It follows the definition of the respective judicial guarantees required for the international and non-international armed conflict and the determination of the threshold for the war crime. Especially for armed groups it is controversial, whether setting up a court leads to the war crime per se. The question is denied, however it is unlikely that the armed groups can master the high responsibilities required by the Statute.