The progress of information and communication technologies have provided each of us with access to far more information than we can comprehend or manage. This emphasizes the difficulty with the resulting semantic heterogeneity of the diverse sources. To make this huge amount of existing information accessible and manageable while also solving the semantic heterogeneity problem it is essential to have a large scale collaborative knowledge base along with a suitable structure as a common ground on which interoperability among people and different systems should be possible. In this book we propose a highly flexible knowledge base system, which takes into account diversity of knowledge and help expert community in building, organizing a high quality knowledge base.