Scientists predict that we could soon use computers to 'see' what we have dreamed about - and perhaps even record dreams to watch the next day.
Psychiatrists at the Max Planck Institute in Munich, Germany think have already demonstrated that brain scanners can see into the dreams of 'lucid dreamers' - people who can control their dreams.
It means that recent breakthroughs in 'reading' the thoughts of waking subjects using brain monitors could apply to dreamers too.
The Planck institute scientists proved that scans of 'lucid dreamers' dreams looked the same as scans of their brain when they do the same thing while conscious.
The research, published in Current Biology, could be used with recently demonstrated 'reconstruction' technology to create moving images of people's dreams.