Introduction

A network is, in its simplest form, a collection of points joined together in pairs by lines. In the jargon of the field the points are referred to as vertices or nodes and the lines are referred to as edges. Many objects of interest in the physical, biological, and social sciences can be thought of as networks and, as this book aims to show, thinking of them in this way can often lead to new and useful insights. This introductory chapter discusses why we are interested in networks and describes some specific networks of note. An overview of the subsequent chapters is presented.