This introduction to graph theory offers a reassessment of the theory's main fields, methods and results. Viewed as a branch of pure mathematics, the theory of finite graphs is developed as a coherent subject in its own right, with its own unifying questions and methods. The work seeks to complement, not replace, the existing more algorithmic treatments of the subject. There are examples, illustrations, historical remarks and exercises at the end of each chapter. The text may be used at various levels. It contains all the standard basic material for a first undergraduate course, while it offers more proofs of several more advanced results for a graduate course. These proofs are described in as much detail as their simpler counterparts, with an informal discussion of their underlying ideas complementing their rigorous step-by-step account. Finally, for the professional mathematician the book affords an overview of graph theory, with its typical questions and methods, its classic results.