Rear Window is a cautionary tale about what happens when you stalk your neighbors: a nurse oils you and someone breaks your other leg.
In Rear Window, Jimmy Stewart plays a man recovering from a broken leg. While recovering, he watches his neighbors comings and goings. Bit by bit, it turns out, their lives have more going on than he expected. Did his neighbor murder his wife?\
Hitchcock did an excellent job of giving the viewer their own doubts: Is Jimmy Stewart just obsessive or did this guy really do something to his wife?
It doesn't help your confidence in the main character when he's caught like this half the film:
(Spoilers) Your doubts are finally relieved when the neighbor attempts to kill Jimmy Stewart to shut him up. He breaks in, chokes Jimmy, and throws him out the window. Jimmy Stewart breaks his other leg and the cops catch the murderer. After he attempted to blind him using a handful of flashbulbs.
By the way, they made this entire set for the movie. This wasn't an existing apartment building.