It is most appropriate that the first volume to appear in the series "Advanced Applications in Pattern Recognition" should be this monograph by Nagao and Matsuyama. The work described here is a deep unification and synthesis of the two fundamental approaches to pat tern recognition: numerical (also known as "statistical") and struc tural ("linguistic," "syntactic"). The power and unity of the meth odology flow from the apparently effortless and natural use of the knowledge-base framework illuminated by the best results of artificial intelligence research. An integral part of the work is the...