Occult

 I sit in my room surrounded by shelves full of ancient books on the occult...

occult is "knowledge of the hidden" or "knowledge of the paranormal", as opposed to facts and "knowledge of the measurable", usually referred to as science. The term is sometimes taken to mean knowledge that "is meant only for certain people" or "must be kept hidden", but for most practicing occultists it is simply the study of a deeper spiritual reality that extends pure reason and the physical sciences. The terms esoteric and arcane can also be used to describe the occult, in addition to their meanings unrelated to the supernatural.