Custodians of knowledge help to facilitate the consult of the vast store of knowledge of Paradise. The custodians are also the exalted teachers of the central universe. Only by indirection and reflectively are the benefits of Paradise knowledge secured in the local universes. 
Custodians of knowledge are the final and living summaries of the vast network of the recording angels, ranging from the seraphim and seconaphim of the local and superuniverses to the chief recorders of the tertiary supernaphim in Havona. 
The superaphic custodians of knowledge are the higher “living epistles” known and read by all who dwell on Paradise. They are the divine records of truth, the living books of real knowledge. It is also inherently impossible for an untruth to gain lodgment in them.  They are in reality living, automatic libraries, sometimes designated the “living library of Paradise”.  They are part of primary supernaphim.  These primary supernaphim who are inherently in possession of universe knowledge are also responsible for its organization and classification.  In Paradise seekers of a knowledge are presented with beings who are exactly what they seek.  Voices of Wisdom in perpetual liaison with Custodians of Knowledge. 
See also: UB 27:5.