Formulation of the Master Plan began in Fiji in 1982 during the Eight Meeing of the International Coordination group of the Tsunami Warning System in the Pacific (ICG/ITSU). At that meeting Resolution VIII.1 was passed which, among other things, requested the IOC Secretariat "to provide support to the preparation, publication, and distribution of a Master Plan". This support was forthcoming and a document 'Tsunami-Where Next?" was prepared and accepted at ITSU IX in Honolulu, Hawaii in 1984 as a document preliminary to the Master Plan. ITSU Resolution IX.1 recommended completion of the Master Plan with with 'a view to adopt the Master Plan at the Tenth Session'. At ITSU X held in Sidney, B.C., Canada, in 1985, the draft Master Plan was reviewed, but it was not approved in its final form until ITSU XI held in Beijing in 1987. This first edition of the Master Plan wa prepared by G.C. Dohler, former chairman of ITSU, in Cooperation with the IOC Secretariat, the Director of the International Tsunami Information Center, the chairman of ITSU, and from comments provided by the National Contacts of the ITSU Member States. The first edition, Doc. IOC/Inf-730, was released on 23 December 1989.At ITSU XV held in Papeete, French Polynesia, in 1995, in consideration of recent technological improvements to the system and increased scientific understanding of the tsunami's nature, the meeting requested the Master Plan be updated and an Editorial Group was established to implement that request. A draft of the second edition was prepared for ITSU XVI held in Lima, Peru for the Member States comments and revisions. Based on their subsequent input, this second edition of the Master Plan wa finalized.The Master Plan for the Tsunami Warning System in the Pacific is designed as a long-term guide for improvement of the Tsunami Warning System based on the analysis off existing components of the system. Since 1987, technological innovations such as enhanced communication networks, improved sseismic analysis techniques, and a low-cost, high-power desktop computers have added greatly to the expectation that improvements recommended in the Plan can be realized for the benefit of the Member States. It is understoot that technological enhancements to the Warning System, as real as the benefits can be, require financial assistance and a plan of action that can gain and maintain Member State support for succesful implementation.In addressing the current operational limitations of the present Tsunami Warning System, the Master Plan specifically recognizes a number of areas requiring improvement. By defining the basic elements of the Tsunami Warning System and the required improvements, the Plan continues as a useful, living document that can be modified and revised to capture benefits associated with technological improvements, undiscoveered funding opportunities, and collaboration amongst Member States.