The concept of knowledge bases originated in artificial intelligence as one side of expert systems-namely, the fundamental body of knowledge available to a domain. KBs are particularly appropriate in knowledge-intensive activities like software development. They offer context-based access to complex information, including informal documents and multimedia, as well as a centralized means of storing and preserving digital assets. KBs can help software engineers with many tasks-from project management and design rationale to version control, defect tracking, code reuse, and staff training and development. We recently implemented an open source KB to support the Consortium for Studying Open Source in Public Administrations. COSPA originated in a EU initiative to study the use of open source software to reduce public administrative software and system support costs. The KB project aimed to build a multilingual knowledge base for comparing and pooling knowledge and experience.