Shakespeare's famous description of sleep holds true.
Indeed sleep "knits up the ravell'd sleeve of care"--
and it gives rise to mysterious dreams as well.

"Blessings light him who first invented sleep!--
it covers a man all over, body & mind, like a cloak;
it is meat to the hungry, drink to the thirsty, heat to the cold,
and cold to the hot;
it is the coin that can purchase all things;
the balance that makes the shepherd equal with the king,
the fool with the wise man..."Miguel de Cervantes,
"Don Quixote"

"Psychologically, sleep can sometimes be a vehicle
for retreating from reality.
All of us have experienced the kinds of stresses in which
the most comfortable things to do upon awakening
would be to duck under the covers and escape reality by sleeping some more..."
Dr. Julius Segal

When you're lying awake with a dismal headache,
And repose is taboo'd by anxiety,
I conceive you may use any language you choose to indulge in,
Without impropriety;
For your brain is on fire--
The bedclothes conspire
of usual slumber to plunder you:
First your counterpane goes,
And uncovers your toes,
And your sheet slips demurely from under you;
Then the blanketing tickles--
You feel like mixed pickles--
So terribly sharp is the pricking,
And your hot and your cross,
And you tumble and toss
till there's nothing 'twixt you and the ticking.
Then the bedclothes all creep
to the ground in a heap,
And you pick 'em all up in a tangle;
Next your pillow resigns
and politely declines
to remain at it's usual angel!
Well, you get some repose
in the form of a doze,
With hot eye-balls and head ever aching,
But you slumber in teems
with such horrible dreams
That you'd very much better be waking...
You're a regular wreck,
With a crick in your neck,
And no wonder your sore
For your head's on the floor,
And you've needles and pins
from your soles to your shins,
And your flesh is a-creep,
For your left leg's asleep,
And you've cramp in your toes,
And a fly on your nose,
And some fluff in your lung,
And a feverish tough,
And a thirst that's intense,
And a general sense
that you haven't been sleeping in clover.
But the darkness has passed,
And it's daylight at last,
And the night has been long--
ditto ditto my song--
And thank goodness they're both of them over!"
Sir William S. Gilbert,
Iolanthe

"The German chemist, Friedrich August Kekule von Strdonitz,
who, had he lived another decade,
might have been awarded the Noble Prize
for purposing the ring form of the benzene molecule,
told how this radical idea came to him in a dream.
In his fantasy, he imagined molecules were dancing about,
some of them with the shape of snakes.
One of these swirling snake molecules seized its own tail in its mouth.
'Like a flash of lightening,' Kekule's sleeping mind recognised
that here lay the explanation for the puzzling properties of benzene!
'Learn to dream, gentleman,' he wrote later.
'Then we shall, perhaps, find the truth.
We must care, however, not to publish our dreams
before submitting them to proof by the awakened mind."
Lorus & Margery Milne

"Dreaming permits each and every one of us to be
quietly and safely insane every night of our lives."
Charles Fisher, M.D.