This book intends to make an understanding of mathematical formalism accessible to students and professionals in a broad range of disciplines. It is written specifically as a text for a one-semester course at the graduate or upper division undergraduate level that covers the various issues of uncertainty, information, and complexity from a broad perspective based on the formalism of fuzzy set theory. No previous knowledge of fuzzy set theory or information theory is required for an understanding of the material in this book. The fundamental notions of classical (nonfuzzy) set theory, classical (two-valued) logic, and probability theory are briefly overviewed in the book. In addition, the basic ideas of classical information theory (based on the Hartley and Shannon information measures) are also introduced. Included iis a glossary of the symbols most frequently used in the text.