Neo4j is an open–source, enterprise–class database with a conventional feature set and a very unconventional data model. Like the databases we're already used to, it offers support for Java, ACID transactions, and a feature–rich query language. But before you get too comfortable, you have to wrap your mind around its most important feature: Neo4j is a graph database, built precisely to store graphs efficiently and traverse them more performantly than relational, document, or key/value databases ever could.

Neo4j is an obvious fit to anyone who thinks they have a graph problem to solve, but this is not many people. It turns out that the most interesting property of Neo4j is its architectural agenda. It wants you to think of the entire world as a graph — as a set of connected information resources. Steeped in the thinking of resource oriented architecture, this NoSQL database wants to change the way you look at your world, and unlock new value in your data as a result.