Tools are essential to aid the ontologist in constructing an ontology, and merging multiple ontologies. Such conceptual models are often complex, multi-dimensional graphs that are difficult to manage. The DL GRAIL has associated tools to shield the ontologist from the logical formalism. An intermediate `template' form is used to represent the conceptualisation, from which the encoding can be generated [38]. These tools also usually contain mechanisms for visualising and checking the resulting model - over and above the logical means for checking the satisfiability of the specified model. The MBO also has an editor for creating and visualising the object based encoding used in that ontology [2]. The frame based system used by EcoCyc also has the GKB editor for handling the conceptualisation and encoding in Frame Based Representations [39]. Such tools are really essential for maintaining complex ontologies that are necessary for capturing knowledge within the biology domain. Other tools support the collaborative development of ontologies over the web (e.g. WebOnto [40]). A survey of tools can be found in [41].