The categories of consciousness etc. described in the Upaniṣads form the background for the entire Vedas. Your consciousness, thinking, meditation and realization are only as good as your ontology. Thus, having a correct ontology of consciousness and being is crucial to success in Self-realization. Here we present our root ontology of consciousness and existence, which we have found to be very useful in researching, practicing, realizing and presenting the Upaniṣads.