Book excerpt: "Polarimetric rotation domain interpretation is an innovation in radar image processing and understanding. Orientation rotation is a basic operator well-known in the classic polarimetry theory and significant advancement has been made in recent years. This book presents new and advanced concepts, theories, and methodologies in radar polarimetry and bridges the gaps between the target scattering diversity, polarimetric radar data, and their practical applications. It provides a comprehensive summarization and investigation of polarimetric roll-invariant features for researchers, students, and engineers"--