concept is not clear that strong to inaccuracies of our perception, while still allowing us to deliver useful, and sometimes vital, information. The study of vagueness in Artificial Intelligence (AI) because it is motivated by a desire to combine this resilience and flexibility into intelligent computer systems. As a goal, however, requires a formal model of clear concepts that will allow us to measure and manipulate the uncertainty resulting from the use of them as a means of conveying information between autonomous agents. This volume outlines a formal representation framework for modeling and reasoning with vague concepts in Artificial Intelligence.