Talbot Mundy 
Caves of Terror [EPUB ebook] 

Talbot Mundy is almost forgotten now but in his works you see ideas used with more lasting success by Sax Rohmer in his Fu Manchu books and Ian Fleming in his James Bond novels that Mundy’s work influenced. In Caves of Terror, a character who seems a sinister version of Gandhi gives two agents of the Strange organisation a frightening tour of a cave beneath an Indian palace where the mystical science of the East is being researched and weaponized.