Compass AE is a set of Engines or Slices-style Rails plugins that incrementally add the functionality of an ERP to a Rails application. It is meant to stay completely out of the directories that a Rails developer would use, so your app and public directories are clean for you to use. It's Object-Relational layer is based conceptually on the phenomenal Data Model Resource Book series by Silverston, as well as the Archetype Patterns work of Arlow and Neustadt. These models have become so widely recognized so as to represent to a certain extent a de facto standard for how to organize ERP-type software. Our choice to create an open source ERP framework by staying close to them at a logical level allows these references to serve as guides for the conceptual underpinnings of the O/R components.