Multidimensional inverse scattering problems (ISP) in inhomogeneous media have important and extensive applications in many areas of interest to the NAVY. Among them are ocean acoustics, electromagnetic properties of sea ice, oceanic biology, and non-invasive testing of some materials, including semiconductors. From mathematical point of view the numerical methods must be based on robust and efficient mathematical algorithms. The development of such algorithms with rapid convergence rates is a challenging task in the theory of multidimensional ISP. In fact, ISPs represent an alternative to the conventional X-ray tomography. The major difficulty of the ISPs is that waves propagate in different (unknown) directions rather than just along straight lines, as it is in the case with X-ray tomography. Thus another term for ISPs is diffusion tomography . We have been working on theoretical studies and computational testing of numerical methods for Inverse Scattering Problems (ISP). Our main efforts have been concentrated on 3-Dimensional ISP. A more minor effort was devoted to 1-D phaseless ISP, that is ISP without phase information.

Inverse Problems is a monograph which contains a self-contained presentation of the theory of several major inverse problems and the closely related results from the theory of ill-posed problems. The book is aimed at a large audience which include graduate students and researchers in mathematical, physical, and engineering sciences and in the area of numerical analysis.

Here is a clearly written introduction to three central areas of inverse problems: inverse problems in electromagnetic scattering theory, inverse spectral theory, and inverse problems in quantum scattering theory. Inverse problems, one of the most attractive parts of applied mathematics, attempt to obtain information about structures by nondestructive measurements. Based on a series of lectures presented by three of the authors, all experts in the field, the book provides a quick and easy way for readers to become familiar with the area through a survey of recent developments in inverse spectral and inverse scattering problems.

The soliton represents one ofthe most important ofnonlinear phenomena in modern physics. It constitutes an essentially localizedentity with a set ofremarkable properties. Solitons are found in various areas of physics from gravitation and field theory, plasma physics, and nonlinear optics to solid state physics and hydrodynamics. Nonlinear equations which describe soliton phenomena are ubiquitous. Solitons and the equations which commonly describe them are also of great mathematical interest. Thus, the dis covery in 1967and subsequent development ofthe inversescattering transform method that provides the mathematical structure underlying soliton theory constitutes one of the most important developments in modern theoretical physics. The inversescattering transform method is now established as a very powerful tool in the investigation of nonlinear partial differential equations. The inverse scattering transform method, since its discoverysome two decades ago, has been applied to a great variety of nonlinear equations which arise in diverse fields of physics. These include ordinary differential equations, partial differential equations, integrodifferential, and differential-difference equations. The inverse scattering trans form method has allowed the investigation of these equations in a manner comparable to that of the Fourier method for linear equations.