The purpose of this tutorial is to help attendees gain sufficient experience of working with OWL and tools to allow them to fruitfully explore new ontologies that they may encounter. In other words, they should be able to do the equivalent of “view source” on an ontology. Also, they will get better fluency in the use and abuse of OWL by examining features, limitations, and workarounds in real contexts, as well as gaining an understanding of the impact of future extensions of OWL, in particular of rules and the proposed revision of the language called OWL 1.1.