This thorough and up-to-date guide to this area of practice the first and only such guide available provides a comprehensive analysis of all the issues arising from multiparty-multicontract arbitrations, including those involving States and groups of companies. The numerous factors and problems analysed in depth include the following: • theories on the basis of which courts and arbitral tribunals determine who are parties to the arbitration clause; • whether an arbitration clause may be extended to non-signatories; • to what extent one can bring to a single arbitration proceeding the various parties who have participated in a single economic transaction through several contracts; • whether a respondent can join other defendants to the arbitration, be they privy to the arbitration agreement or third parties; • whether a party to a complex contractual structure can intervene voluntarily in the proceedings; • under what conditions separate arbitration proceedings may be consolidated; • how and to what extent one can overcome the inconveniences that arise from having several parallel proceedings; • enforcement of multiparty-multicontract awards. It also includes an analysis of relevant national case law based on nearly 200 court decisions from the United States, France, Switzerland, England, Australia, Canada, Belgium and other countries.