From the reviews: "One of the main objectives of rough set theory is to find reasonable extensions for rough sets in known techniques and results about sets. ... I highly recommend this book to students and researchers who are already familiar with the basic ideas of rough set theory and want to learn about the latest developments. In principle, the book should also be accessible to other readers with a mathematical background, even if they are not very familiar with rough sets." (V. Kreinovich, ACM Computing Reviews, November, 2010)