The presentation will describe the challenges, benefits, and opportunities resulting from converting an archival collection of approximately 750,000 files to JATS. The goal was to migrate the American Institute of Physics (AIP) and member society archival collection from multiple generations of proprietary markup to an industry standard to create a true archive, all managed within a new, more controlled content management system. Integral to the process was the adoption and application of the XML technologies XSLT, XPath, and Schematron to transform and check the content. Sounds straightforward doesn't it? Perform a thorough document analysis, map out the transformation rules, convert the data. But is it? Have you accounted for all historical variations, generated text, metadata, nomenclature variations on XML file assets? Beside your core, don't forget about reuse for other products, edge cases, online presentation, distribution channels and staff training!