Originating from Common Law countries, the summary determination of manifestly unmeritorious claims (or defenses) is still quite unknown among civil-law practitioners. By allowing arbitral tribunals to dismiss, on the basis of limited exchanges between the parties and within shortened deadlines, claims or defenses that are manifestly without merit, this tool is an expression of the general willingness to improve efficiency and control costs in international arbitration. Although the use of summary procedures in international arbitration has given rise to criticism, particularly with respect to due process rights, several arbitral institutions have adopted rules providing for the arbitrator’s power to summarily dispose of a claim or defense. Used with care and effectiveness by arbitral tribunals, this tool reinforces the efficiency of arbitral proceedings thereby contributing to its attractiveness.