Graphs are extremely useful in modelling systems in physical sciences and engineering problems, because of their intuitive diagrammatic nature. This text gives a reasonably deep account of material closely related to engineering applications. Topics like directed-graph solutions of linear equations, topological analysis of linear systems, state equations, rectangle dissection and layouts, and minimal cost flows are included. A major theme of the book is electrical network theory. This book is basically intended as a reference text for researchers, and requires a certain level of mathematical maturity. However the text may equally well be used for graduate level courses on network topology and linear systems and circuits. Some of the later chapters are suitable as topics for advanced seminars. A special feature of the book is that references to other published literature are included for almost all the results presented, making the book handy for those wishing to continue with a study of special topics This is the first book to comprehensively cover chromatic polynomialsof graphs. It includes most of the known results and unsolved problemsin the area of chromatic polynomials. Dividing the book into threemain parts, the authors take readers from the rudiments of chromaticpolynomials to more complex topics: the chromatic equivalence classesof graphs and the zeros and inequalities of chromatic polynomials. Preface; Contents; Basic Concepts in Graph Theory; Notation; Chapter 1 The Number of -Colourings and Its Enumerations; Chapter 2 Chromatic Polynomials; Chapter 3 Chromatic Equivalence of Graphs; Chapter 4 Chromaticity of Multi-Partite Graphs; Chapter 5 Chromaticity of Subdivisions of Graphs; Chapter 6 Graphs in Which any Two Colour Classes Induce a Tree (I); Chapter 7 Graphs in Which any Two Colour Classes Induce a Tree (II); Chapter 8 Graphs in Which All but One Pair of Colour Classes Induce Trees (I); Chapter 9 Graphs in Which All but One Pair of Colour Classes Induce Trees (II)