The logo on the cover of the black magic book is a monogram whose letters can spell "NECRONOMICON". The Necronomicon was a fictional book on black magic invented by 1930's writer H. P. Lovecraft. Some of Lovecraft's friends (Robert Bloch and Robert Howard) had stories adapted for "Thriller".
The painting hanging above Radan Asparos' drawing room fireplace is Cristofano Allori's 1613 work "Judith with the Head of Holofernes." The original was acquired by Charles I of England and is part of the Royal Collection.
At one time, the "black magic book" is open while Harry Townes fashions a cross. The pages are from the "The Cottage Bible and Family Expositor", an 1835 Bible with reference material. One line reads "King over all the children of pride" (Job 41:34) just before "CHAPTER XLII".