The general objective of the thesis is to provide domain independent, and resource independent methods and tools for speeding up the ontology development process and is achieved by reusing and re-engineering as much as possible available non-ontological resources (NORs). To fulfil this overall goal, we have decomposed it into the following methodological and technological objectives: The definition of methodological aspects related to the reuse of non-ontolo-gical resources for building ontologies. The definition of methodological aspects related to the re-engineering of non-ontological resources for building ontologies. The creation of a library of patterns for re-engineering non-ontological resources into ontologies. The development of a software library, NOR2O, that implements the suggestions given by the re-engineering patterns.