9.1 Introduction9.2 Preliminaries9.3 Fuzzy Rough Set‐Based Attribute Reduction9.4 Approaches for Semisupervised and Unsupervised Decision Systems9.5 Decision Systems with Missing Values9.6 Applications in Classification, Rule Extraction, and Other Application Areas9.7 Limitations of Fuzzy Rough Set Theory9.8 ConclusionReferences