Skeleton Key is UB Only.
Novel originally copyright 1943.
Front cover: Yellow
A yellow key is approaching a keyhole that is dripping blood.
Crime map on back cover in brown, white, yellow and green.
Blue background with title, author and publisher and publisher's logo in black and white.
A Dell Mystery keyhole logo
Offord, Lenore Glen, 1905-, “Skeleton Key,” Digital Collections - University at Buffalo Libraries, accessed May 11, 2021, https://digital.lib.buffalo.edu/items/show/29253.