The Climax (1944)

A very enjoyable romp from the 40's about unrequited love driving a man to obsession, selfishness and murder, and you really can't go wrong with Boris Karloff, particularly from this vintage. This is especially enjoyable if you're a fan of opera at all. New York City-born director Waggner, most famous for 'The Wolf Man', is decent at this sort of thing, though he got relegated the last phase of his career to TV-work (such as the 60's 'Batman').

Karloff's first colour film (and in Technicolor, no doubt), it's also famous for using the same sets as 'The Phantom of the Opera', made the previous year--the oldest surviving movie set. I came across this in an excellent 5-film pack of Karloff-starred thrillers from the late 30's and early 40's. Both the boxed set and this individual film are highly recommended to fans of the star's work.