An ontology is a formal description of concepts and relationships that
can exist for a community of human and/or machine agents. The notion of
ontologies is crucial for the purpose of enabling knowledge sharing and
reuse. The Handbook on Ontologies provides a comprehensive overview of
the current status and future prospectives of the field of ontologies
considering ontology languages, ontology engineering methods, example
ontologies, infrastructures and technologies for ontologies, and how to
bring this all into ontology-based infrastructures and applications that
are among the best of their kind. The field of ontologies has
tremendously developed and grown in the five years since the first
edition of the "Handbook on Ontologies". Therefore, its revision
includes 21 completely new chapters as well as a major re-working of 15
chapters transferred to this second edition.