Graduated in law and philosophy, professor of law. Prof. Kwiecień is a member of the Permanent Court of Arbitration and an arbitrator at the Court of Conciliation and Arbitration within the OSCE. In his research and didactic activity, he deals with international law, in particular with regard to the legal position of states, the theory and philosophy of international law, the law of treaties, the use of armed force, as well as European Union law and legal philosophy.