While everyone is rushing towards big data and generalised AI, we should not forget the other side of data analysis. There is always situations where we have to deal with limited and imperfect data. This book provides a systematic coverage on the theoretical systems and practical applications of grey systems with the latest development in the field. It helps its readers get into the field with a systematic understanding of its background knowledge and its latest technology development from the leading experts. It is an essential book for postgraduates and researchers who need data analysis with imperfect data.