This volume provides a collection of twenty articles containing new material and describing the basic concepts and characterizing features of rough set theory and its integration with fuzzy set theory, for developing an efficient soft computing strategy of machine learning. Written by leading experts from all over the world, the contributions demonstrate how rough-fuzzy hybridization can be made in various ways to provide flexible information processing capabilities for handling different real-life, ambiguous decision-making problems. This volume provides a balanced mix of theory and application.