To die, to sleep;

To sleep: perchance to dream: ay, there's the rub;
For in that sleep of death what dreams may come
When we have shuffled off this mortal coil,
Must give us pause...

-- William Shakespeare - To be, or not to be
(from Hamlet 3/1)

Jacob's Dream woodcut, Lubeck Bible 1494

This week's Science Times in the New York Times has a series on sleep and dreaming, including articles on sleep deprivation, nightmares, and sleeping pills.

1888 woodcut, French astronomer Camille Flammarion