Abstract : AMI was chosen as the ATLAS dataset selection interface in July 2006. It is the main interface for searching for ATLAS data using physics metadata criteria. AMI has been implemented as a generic database management framework which allows parallel searching over many catalogues, which may have differing schema. The main features of the web interface will be described; in particular the powerful graphic query builder. The use of XML/XLST technology ensures that all commands can be used either on the web or from a command line interface via a web service. We also describe the overall architecture of ATLAS metadata and the different actors and granularity involved, and the place of AMI within this architecture. We discuss the problems involved in the correlation of metadata of differing granularity, and propose a solution for information mediation.