Talbot Mundy 
Caves of Terror [PDF ebook] 
The Gray Mahatma

Action-adventure writer Talbot Mundy made his name in the genre with a series of fast-paced, fan-pleasing page-turners set in the Middle East, India, and Africa, based largely on his own experiences these regions. Later in his life, however, Mundy became increasingly interested in mysticism and Theosophy. Caves of Terror blends both of these components seamlessly, combining supernatural elements with a thrill-a-minute plot.