In part one of this book, we’ll take a high-level view of graphs. First, I’ll introduce you to what graphs are and how they can be used across a variety of domains, with some detailed case studies. Then, we’ll dive a little deeper into graph models of data, how they might be different from standard relational models of data, and how you can create graph data models from your data. I’ll introduce you to the two tools that we’ll use throughout the book: Gephi and KeyLines. I’ll use both Gephi and KeyLines in later chapters to illustrate how you can create graph visualizations of your own—for you own use, with Gephi, or as part of a visualization application, using KeyLines.