This book exposes the core business processes that Compiere Open Source ERP provides, and compares its features to its counterpart Microsoft Dynamics NAV. It puts into perspective the advantages of Open Source ERP and out-of-the-box processes that we can obtain from it. The study at hand proposes a new evaluation approach based on functional requirements of ERP systems correlated with the industry target. Both ERP systems are assessed according to the business processes they support and 156 criteria are used to offer a clear picture of the software functional capabilities. The criteria concentrate on the functionality modules, user friendliness, support, and internationalization functions. Contrary to the belief that Dynamics NAV, as a product of Microsoft Corporation, would be significantly better than Compiere, an Open Source ERP system, it has been a surprising discovery that Compiere has achieved a very good score. Nevertheless, the readers of this book will find out intriguing results on Open Source ERP Systems and learn how to assess ERP system based on software core capabilities and company specific needs.