In the first chapter of this book, we wanted to give you a first look at some of the concepts that underpin the subject of this book, the graph database Neo4j. We introduced the history of graphs, explained some of the principles that are being explored in the fascinating mathematical field of graph theory, and provided some examples of other academic and functional domains that have been benefiting from this rich, century-long history. The conclusion of this is plain and simple: Graphs Are Everywhere. Much of our world is in reality dependent on and related to many other things—it is densely connected, as we call it in graph terms. This of course has implications on how we work with the reality in our computer systems, how we store the data that describes reality in a database management system, and how we interact with the system in different kinds of applications.

In the next chapter, we will start applying this context to the specific part of computer science that deals with graph structures in the field of database management systems.