Graph databases – like Neo4j – are a powerful tool for storing and querying highly connected data. Indeed Neo4j can be thousands of times faster than relational databases for such connected data, making it popular for managing complex data across many domains from finance to social, and telecoms to geospatial. In this book, Ian, Emil, and I explain what a graph database is and how it can be used to gain insight into business critical data. We show how modern graph databases are an excellent choice for both OLTP and OLAP data stores and demonstrate the myriad of use-cases for the Neo4j database.