Scatterers one meets in the fields are commonly known to have complex shape and structure, and many theoretical methods to treat the interaction of radiation with such particles have been developed. However, most of these approaches are still too computationally demanding for proper modelling of the optical properties of disperse media containing non-spherical inhomogeneuos scatterers. The main idea of this book is to provide a reader with thorough information and various tools to solve the problem. The authors review the contemporary light scattering methods to introduce efficient versions of the fast exact methods as well as of some approximate ones. They also summarise theoretical studies of the applicability ranges of the methods, and formulate and illustrate the principal effects of scatterer shape and structure variations on the optical properties. Cosmic dust, atmospheric aerosols, nanosensors and other scatterers are considered as applications.