The Prisoner in the Opal by A.E.W. Mason

Sphere Books 
1974 
Paperback 
Volume 10 in the Dennis Wheatley Library of the Occult 
287 Pages 
11 x 18cm 

Condition: Fair

Supernatural mystery following an investigation involving ancient secrets, unusual phenomena, and a mysterious object. Blending adventure, crime, and elements of the uncanny, the novel reflects the early 20th-century fascination with archaeology, hidden histories, and unexplained events.