Tolerance graphs can be used to quantify the degree to which there is conflict or accord in a system and can provide solutions to questions in the form of "optimum arrangements." Arising from the authors' teaching graduate students in the U.S. and Israel, this book is intended for use in mathematics and computer science, where the subject can be applied to algorithmics. The inclusion of many exercises with partial solutions will increase the appeal of the book to instructors as well as graduate students.