A concept that Marius describes to Lestat, it captures his longing for an eternal preservation of values and identity. Since Marius fears chaos and ultimate meaninglessness, and since he cannot tolerate the possibility that even the simplest memories might be lost, he wants to believe that there is an omniscient force in the universe that keeps track of everything. He longs for something that possesses extended awareness, to give meaning and structure to life and death. As a vampire, he sees himself as the embodiment of this concept when he tracks human progress across a millennium. (VL 398)
This concept is significant for Rice. The idea that she might die and be forgotten, or that she may never find out why certain events happened, signifies and unacceptable degree of chaos in the universe. Such darkness and disorder do not make sense to her.
Taken from Katherine Ramsland's The Vampire Companion.
We see a glimpse of Marius' interest in continuous awareness in the Queen of the Damned. When Marius finds Enkil dead, he laments the loss of not only the King, but a being who has seen and learned so much. In Enkil, Marius saw a vision of what continuous and eternal awareness could be. That all the information stored in Enkil was gone upset Marius.
In a scene deleted from Tale of the Body Thief, Marius employs Khayman to kidnap the mortal Lestat and bring him to his home. In the chapter, Marius has a telescope and he tells Lestat all about his theories of continuous awareness and his search for it.
This is why Marius seeks to know everything, to understand and collect every tendril of knowledge. He cannot accept that any information can die and be lost. There must be some being alive who can know and understand everything. Marius will either be this being or find the being.