@GoldsteinA,
So, apartment building? Two-family house? City block? Same home as you?
Apartments can be home to lots and lots of people, of course. Landlords generally don't investigate the creep factor. They mainly just want people who pay their rent on time with checks that don't bounce, and aren't felons.
Your recourse is to move.
Two-family house? Same thing. City block? Same thing?
Same home as you (as in, you live in one bedroom and he lives in the other)? Kinda the same thing.
I am sensing a pattern here.