Prepares graduate students with a basic knowledge of semigroups to begin original research in partial transformation semigroups. Introduces and rigorously describes symmetric inverse semigroups, and documents how path notation extends beyond them to the partial transformation semigroup. Unifies the classical finite symmetric group theory with its semigroup analogue, and contains new proofs and theorems. Each chapter ends with a historical perspective. Member prices are $29 for individuals and $39 for institutions. Annotation copyrighted by Book News, Inc., Portland, OR