The Jato API converts XML documents into Java objects and back again. In January, Andy Krumel publicly released the API in beta form at SourceForge. Based on the observation that transformations are mechanical and tedious, with Jato a simple XML script describes the XML/Java mapping. In this article, the first of three, Andy explains how to use Jato to perform basic Java-to-XML and XML-to-Java transformations. In Part 2, he will focus on performing complex Java-to-XML transformations. Part 3 will explore converting an XML document into Java application objects.