I think we all dream. theres a Delta wave brain pattern and dreaming does happen at this level, however training yourself to remember dreams is something we have to work at sometimes. there can be periods of time or years even, when it appears we are not dreaming because we are concentrating so heavily on our lives and sensory perceptions and physical experiences and thats ok too. yet, if you've ever day dreamed, then you can be assured you are doing the night dreaming.
cheers, alysia

Alysia's right..I believe we all dream every night, its just a matter of remembering them. 

That takes some conditioning..telling yourself to remember.

Also, waking with an alarm clock makes it harder to recall also..the startling awake tends to make us forget.

I didn't dream any to speak of for almost six years.  That was because the situation I was in did not allow me to get more than a half hour of very light sleep at any time.  It was also extremely unhealthy!  Since I've changed things enough that I can get a passable nights sleep most nights, it'a almost scary how much I dream ;>).  Funny thing was, it took me a long time to realize I wasn't sleeping well...I'd pretty much go right to sleep when I went to bed, from sheer exhaustion, and not remember a lot of being awakened in the night, only really figured it out when it got so bad I couldn't ignore it any more.