This pre-war 1934 Dennis Wheatley classic races along in an Indiana Jones cum Wilbur Smith sort of way before it returns to Wheatley's gentler, cerebral and familiar type of adventure-style. Written upon his return from a tour of South Africa, it is full of rich period descriptions of pre-war (The Union of) South Africa and the dangerous mountainous raft-ride is particularly well described. Probably not one of his best adventure nor horror tales, but if you're into adventure, terror, diamonds, South Africa, and the Kalahari then this one's a rip-roaring must!