My poor poor baby.
The Unknown is directed by Henry Levin and adapted to screenplay by Charles O'Neal and Dwight Babcock from the radio play written by Malcolm Boylan and Julian Harmon. It stars Karen Morley, Jim Bannon and Jeff Donnell. Music is by Alexander Steinert and cinematography by Henry Freulich.
A wonderfully good old fashioned spooky house mystery finds a group of relatives arrive at a big mansion estate for the reading of a will. Pretty soon strange occurrences and accidents are the order of the night.
Clocking in at just seventy minutes in run time, Levin's picture doesn't have time to bore or bother with pointless filler. Standard creepy house rules apply here, shadows dominate the visuals (Freulich's photography excellent), which accentuate uneasy atmosphere as characters trawl through secret passageways, barely lit corridors, the ominous staircase and even a mausoleum that sits next to the house. 
The sound mix is important because you have to have creaks and groans, and the unnerving cry of a child in the night, all is spot on there. While the characters are a ripe blend of eccentrics, suspicious suspects,intrepid investigators and a dainty dame. The mystery element holds strong throughout, and while the resolution is hardly a bolt from the blue, it pays off well enough to round out a good time spent with the viewing. 6.5/10