While we sleep and dream, the waking world
goes on without us - unaffected by our absence.

But what if this weren't the case?

What if sleep, and more specifically, dreaming,
could change the world, could alter reality; and
do so on a global scale?

For example, imagine someone dreams that the
problem of overpopulation is eliminated; and
then wakes to find that billions of people had
vanished overnight.

And what if Science stumbled upon this strange
dream-power and sought to harness it in order
to better the world?

This is the premise of Ursula K. Le Guin's
The Lathe of Heaven, a novel nominated for
both the Hugo Award and Nebula Award
back in 1971.