This presentation will discuss 'reconciliation' work, or the work of aligning your metadata with external datasets. Going through a number of possible reconciliation workflows and tools - from GUIs to scripting, using traditional authorities and linked open datasets, either capturing URIs, preferred form terms, or other information - I will show how metadata reconciliation is increasing in importance for metadata work and for creating data ecosystem coherence. I also will mention some of the issues, particularly of scalability, the relatively high accuracy rate needed for library metadata work, issues with false positives, and propagation of data changes over time. This work begins to frame some issues too around the concept of library 'authorities' and how it should change. Finally, I will present this work to show one way a wider range of technology and data skill sets can work together on a common workflow, thus increasing mutual understanding across functional silos.