My cave is a warm and welcoming space, but not a bright place. The darkness is nearly complete in many areas. The comfortable darkness enfolds you as you progress deeper into my cave, with occasional punctuation from ever-burning candles in sconces here and there, and an occasional chamber lit for a purpose.
The library is one such chamber, with low, shadowless ambient lighting in most of the room, and reading lights near a selection of comfortable chairs as well as work tables. The associated stacks, however, are reasonably well lit near the door and get darker as you wander afield into the obscure topics.
That lighting serves a purpose. A visitor (welcome or not) who is afraid of the dark will not get very far before they must face their fears. A welcome visitor may be accommodated. The other kind may find that their fears have some basis in reality.
Why do I live this way?
Contrary to rumor, I am not afraid of the light, or of open spaces. After all, there are a few rooms in my cavern which are large enough to house several houses.
I am simply selfish of my privacy.
I enjoy being not fully understood by the town.
It keeps my days undisturbed by solicitors. It keeps me out of the public eye. It allows my age to not usually be a matter of speculation.