Door Without a Key is an expression used by Dion Fortune in Moon Magic, London, Aquarian Press, 1956, page 91:

“I will tell you what I did, putting all my cards on the table, for it shows how we used the Door Without a Key to escape the Lord of This World, who is Moloch, and take refuge in the Secret Kingdom, which is the dark side of the Moon, the side She turns away from earth.

“The Door Without a Key is the Door of Dreams; it is the door by which the sensitive escapes into insanity when life is too hard for them, and artists use it as a window in a watch tower. Psychologists call it a psychological mechanism; magicians call is magic, and the man on the street calls it illusion or charlatanry according to taste. It does not matter to me what it is called, for it is effectual.

“I made the astral projection by the usual method; that is to say, I pictured myself as standing six feet in front of myself and then transferring my consciousness to the simulacrum thus created by my imagination and looked at the room through its eyes . . .”

Quote from same book, page 176:

O great god Pan, return to earth again;

Come at my call, and show thyself to men.

Shepherd of goats, upon the wild hill’s way,

Lead thy lost flock from darkness into day.

Forgotten are the ways of sleep and night;

Men seek for them whose eyes have lost the light.

Open the door, the door that hath no key – 

The door of dreams whereby men come to thee.

Shepherd of goats, oh answer unto me!