Then I turned over in my sleep and began to dream deeper still: and I dreamed that I saw John growing tall and lank till he ceased to be a child and became a boy. The chief pleasure of his life in these days was to go down the road and look through the window in the wall in the hope of seeing the beautiful Island. Some days he saw it well enough, especially at first, and heard the music and the voice. At first he would not look through the window into the wood unless he had heard the music. But after a time both the sight of the Island, and the sounds, became very rare. He would stand looking through the window for hours, and seeing the wood, but no sea or Island beyond it, and straining his ears but hearing nothing except the wind in the leaves. And the yearning for that sight of the Island and the sweet wind blowing over the water from it, though indeed these themselves had given him only yearning, became so terrible that John though he would die if he did not have them again soon. He even said to himself, 'I would break every rule on the card for them if I could only get them. I would go down into the black hole for ever if it had a window from which I could see the island.' Then it came into his head that perhaps he ought to explore the wood and thus he might find his way down to the sea beyond it: so he determined that the next day, whatever he saw or heard at the window, he would go through and spend the whole day in the wood.
~C.S. Lewis, The Pilgrim's Regress, Chapter IV "Leah for Rachel" (1933)