This paper reviews and compares the main methodologies, tools, and languages for building ontologies, as well as their relationships. The authors highlight the need for a common integrated workbench to facilitate ontology development, exchange, evaluation, evolution, and management. They discuss various methodologies, such as METHONTOLOGY and CO4, and tools like Protégé 2000 and WebODE, and languages like KIF, Ontolingua, and OWL. The paper concludes by emphasizing the lack of integration among existing tools and the need for a comprehensive workbench to support the entire ontology lifecycle, including knowledge acquisition, edition, browsing, integration, merging, evaluation, and translation. The authors also suggest the development of middleware services to support the use of ontologies in other systems and the creation of ontology application development suites to promote the widespread adoption of ontology-based applications in the Semantic Web context.This paper reviews and compares the main methodologies, tools, and languages for building ontologies, as well as their relationships. The authors highlight the need for a common integrated workbench to facilitate ontology development, exchange, evaluation, evolution, and management. They discuss various methodologies, such as METHONTOLOGY and CO4, and tools like Protégé 2000 and WebODE, and languages like KIF, Ontolingua, and OWL. The paper concludes by emphasizing the lack of integration among existing tools and the need for a comprehensive workbench to support the entire ontology lifecycle, including knowledge acquisition, edition, browsing, integration, merging, evaluation, and translation. The authors also suggest the development of middleware services to support the use of ontologies in other systems and the creation of ontology application development suites to promote the widespread adoption of ontology-based applications in the Semantic Web context.