History shows that in armed conflicts prisoners of war and civlians may become victims of irregular or unfair criminal proceedings or sentencing. The court may not be independent or impartial, the accused unaware of the charges or not provided with counsel, not given the opportunity to present evidence on his own or to appeal the judgment to a higher court of law. The legislation may even rest upon discriminatory grounds denying equality before the law. It is still a reality in the 21st century. Similarly, numerous examples exist to tell us that persons accused of crime have been denied a fair trial in peace time. They may have been tortured to obtain a statement or confession, or arbitrarily deprived their liberty, suffering from illegal searches or seizures, interceptions of communications, tried twice in violation of the ne-bis-in-idem-principle, or obstructed from having legal advice from counsel. At the international courts, as well in national jurisdictions, there are rules that define such situations as a crime. They may appear as general clauses to be filled with contents from other, related rules or principles of law, or be a specific crime. This book provides an analysis of article 8 of the Statute of the International Criminal Court and the crime of irregular or unfair criminal proceedings or sentencing as a war crime. In so doing the 1949 Geneva Conventions are discussed together with international human rights law and the law of nations. The study also provides an analysis whether in international law there is a crime of summary trials or executions. Ulf Lundqvist is former Judge Referee to the Supreme Court of Sweden and Ass. Prof. in civil and criminal procedural law.