System scientists wielding the tools of fuzzy math have a central role to play in modeling increasingly complex engineering and operations research problems of an interdisciplinary nature, according to the author. To cope with real world uncertainties and provide a philosophical and practical guide to system modeling, system identification, and decision-making, several methodologies are presented from probability theory, possibility theory, and fuzzy mathematics. Appends material on sets, relations, and mapping; measuring forecast accuracy; clustering; measuring spaces and integrals; unbiasedness of estimators; statistical reasoning; and frequency analysis. Wolkenhauer is affiliated with the U. of Manchester Institute of Science and Technology"