Well-written text illustrates development of graph theory and application of its principles in methods both formal and abstract. Practical examples explain theory's broad range, from behavioral sciences to cybernetics. From the circuit diagrams of physics and electronics to psychology's sociograms and the communications networks employed by operational research, an extraordinary variety of disciplines rely on graphs to convey fundamentals as well as finer points. With this concise and well-written text, any reader possessing a firm grasp of general mathematics can follow the development of graph theory and learn to apply its principles in methods both formal and abstract. The first full-length book in English on graph theory, this volume is the work of a distinguished mathematician who has made significant original contributions to the subject. His frequent use of practical examples illustrates the theory's broad range of applications, providing a versatile mathematical technique appropriate to the behavioral sciences, information theory, cybernetics, and other areas, in addition to mathematical disciplines such as set and matrix theory. The author begins with the simplest theorems, stated in the most general terms possible for economy of thought and exposition. He gradually builds to more complex theorems, expressed in more exacting proofs and reflecting the results of extensive studies. Definitions from algebra and the theory of sets appear at the start and are supplemented as needed. Students, teachers, and anyone interested in effective communication of research results will find this text a valuable source of instruction.