I have had many Lucid dreams within the first hour of sleeping.
Sometime's some pretty powerful one's.
Sometime's I only sleep three to four hours, and I can recall
many very crazy dream's in this period.

I think I remember reading in exploring the world of lucid
dreaming, that you can dream in other sleep periods.
It's just that, most people only remember stuff from REM
period's.

I could be wrong, but I seem to be able to remember a lot
of dream's durring time's I should not be able to.