In this article I am going to introduce you to the open source, free (GNU LGPL license), native XML database eXist (www.exist-db-org). Data is important, no question about it. Data that can't be queried is not very useful. Users expect to have good query response time. From my personal experience and testing, I am confident in saying that eXist is a fairly good database. It has very good query response time, it is very user friendly, it's easy to set up and operate, and it's written in Java, therefore it is platform independent.