International arbitral and judicial awards are of considerable importance, for they are a "subsidiary means for the determination of the rules of law" as provided in Article 38 of the Statute of the International Court of Justice. They are also important from the point of view of the progressive development of international law, a task which Article 13 of the Charter places under the responsibility of the General Assembly of the United Nations.

Prior to the publication of the first four volumes of the United Nations Reports of International Arbitral Awards, there existed no systematic collection of such decisions. Yet the need of one had been felt for a long while by the various national and international bodies concerned with international law and by all those interested in its development. Accordingly, the Secretariat of the United Nations and the Registry of the International Court of Justice together considered what steps could be taken to prepare such a collection.

With regard to the first four volumes, it was, decided that, owing in particular to the facilities offered by the Carnegie Library in the Peace Palace, the work could best be done in the Registry at The Hague. The International Court authorized the Registrar to undertake it, provided that the business of the Court itself permitted and that the Court's responsibility as such was in no way involved. All subsequent volumes were prepared by the Codification Division of the Office of Legal Affairs.

It was decided to limit the collection strictly to international decisions, i.e. those rendered between States. Awards between a private individual or body and a State have been omitted. It was subsequently decided to also include in the collection of international decisions those rendered between States and international organizations.

At the time of the preparation of the first volume of RIAA in 1948, the decision was made to exclude arbitral awards contained in highly authoritative collections which were easily accessible at the time. However, with the passage of time, the accessibility of the awards in these collections has diminished since many of them are out of print and no longer available, despite the continuing historical and legal significance of the awards. Therefore forthcoming volumes of the publication will be devoted to a collection of international decisions rendered from the late eighteenth century to the mid-twentieth century.

In order to preserve the accuracy of the awards the historical names of the Parties at the time of the awards have been retained.