Introduction. I: Nature of the compulsory jurisdiction of the International Court of Justice. A. The consent of the parties to adjudicate a specific dispute as a basis of the Court's jurisdiction. B. The compulsory jurisdiction as one of the options provided by the Statute for the States to express their consent to adjudicate disputes before the Court. II: Reservations in the unilateral declarations under Article 36(2) and the application of reciprocity. A. Permissibility and legal nature of reservations. B. Reciprocity as a reservation in a declaration. III: Application of reciprocity to reservations in unilateral declarations under Article 36(2). IV: Reservations ratione temporis and application of reciprocity. A. Reservations limiting jurisdiction ratione temporis. B. Time-limits of declarations: entry into force. C. Time-limits of declarations: duration and termination. V: Reservations ratione materiae and the application of reciprocity. A. Reservation excluding disputes falling under the domestic jurisdiction of a State. B. Reservation excluding territorial disputes. C. Reservations in declarations under the Optional Clause and reservations to treaties. D. Reservations excluding disputes in regard to which the parties agree to have recourse to another method of settlement. E. Disputes considered both by the International Court of Justice and the Security Council. F. The multilateral treaty reservations. VI: Reservations ratione personae and the application of reciprocity. Conclusions. Annexes.