TheAdvancedResearchWorkshop"NewTrendsinIntegrabilityandPartial Solvability"(ARW. 978791) tookplaceinthebeautifulsettingoftheFaculty ofMedicineofC adizUniversity'smainroomonJune13-15,2002. Although thenumberofparticipantswas 30, thelectureswereattendedbymorethan one hundred researchers from around the world who were also attending the NEEDS 2002 meeting. Theaim of the organizers was to take advantage of these events to bring together researchers from the ?eld of integrable systems and/or from the particular subject of partial integrability, in view of the current interest in combining methods and ideas arising from both areas. A widevariety of topics were covered in the talks andthe subsequent discussions, including the analysis of reductions and solutions of integrable nonlinear partial di?erential equations and dynamical systems, new me- ods for the analysis of initial-boundary value problems for linear partial di?erential equations, quasi-exactly solvable Bose systems, the geometric theory of ordinarydi?erential equations, exactly and partially solvable spin models, the theory of nonlocal symmetries of di?erential equations, and superintegrable systems. Theworkshop revealed the growing importance of the theory of integrable system as well as the emerging theory of partially solvable systems. The present volume contains a series of invited contributions describing the background and recent developments of the main subjects discussed in the workshop. Special emphasis has been laid on providing self-contained and detailed presentations of the theory. M. J. Ablowitz and J. Villarroel give a detailed description of the inverse scattering for the KP equation, a keystone in the theory of integrable s- tems."

The idea of devoting a complete book to this topic was born at one of the Workshops on Nonlinear and Turbulent Processes in Physics taking place reg ularly in Kiev. With the exception of E. D. Siggia and N. Ercolani, all authors of this volume were participants at the third of these workshops. All of them were acquainted with each other and with each other's work. Yet it seemed to be somewhat of a discovery that all of them were and are trying to understand the same problem - the problem of integrability of dynamical systems, primarily Hamiltonian ones with an infinite number of degrees of freedom. No doubt that they (or to be more exact, we) were led to this by the logical process of scientific evolution which often leads to independent, almost simultaneous discoveries. Integrable, or, more accurately, exactly solvable equations are essential to theoretical and mathematical physics. One could say that they constitute the "mathematical nucleus" of theoretical physics whose goal is to describe real clas sical or quantum systems. For example, the kinetic gas theory may be considered to be a theory of a system which is trivially integrable: the system of classical noninteracting particles. One of the main tasks of quantum electrodynamics is the development of a theory of an integrable perturbed quantum system, namely, noninteracting electromagnetic and electron-positron fields."

TheAdvancedResearchWorkshop"NewTrendsinIntegrabilityandPartial Solvability"(ARW. 978791) tookplaceinthebeautifulsettingoftheFaculty ofMedicineofC adizUniversity'smainroomonJune13-15,2002. Although thenumberofparticipantswas 30, thelectureswereattendedbymorethan one hundred researchers from around the world who were also attending the NEEDS 2002 meeting. Theaim of the organizers was to take advantage of these events to bring together researchers from the ?eld of integrable systems and/or from the particular subject of partial integrability, in view of the current interest in combining methods and ideas arising from both areas. A widevariety of topics were covered in the talks andthe subsequent discussions, including the analysis of reductions and solutions of integrable nonlinear partial di?erential equations and dynamical systems, new me- ods for the analysis of initial-boundary value problems for linear partial di?erential equations, quasi-exactly solvable Bose systems, the geometric theory of ordinarydi?erential equations, exactly and partially solvable spin models, the theory of nonlocal symmetries of di?erential equations, and superintegrable systems. Theworkshop revealed the growing importance of the theory of integrable system as well as the emerging theory of partially solvable systems. The present volume contains a series of invited contributions describing the background and recent developments of the main subjects discussed in the workshop. Special emphasis has been laid on providing self-contained and detailed presentations of the theory. M. J. Ablowitz and J. Villarroel give a detailed description of the inverse scattering for the KP equation, a keystone in the theory of integrable s- tems."