A masterpiece of the locked-room / impossible murder genre, this golden age murder mystery, written in 1944, is great fun.
It has all the elements required for a golden age mystery -- a secluded location at which all the suspects are stranded for the duration. A dashing hero who turns detective. A plucky heroine. And an assorted number of house guests, many of whom have a motive for the crime. Then it throws in some clever puzzles, including the footprints that begin and end in an unbroken expanse of snow, a locked room, a flying murderer and the disappearance from a watched room of one of the suspects.
Atmospheric yet still retaining a fun, light, "figure-this-out-if-you-can" attitude; it all makes this a perfect book for mystery lovers and those who enjoy a touch of the supernatural in the mix.