It came out of nowhere and turned men into mummies. It threatened the construction of the mighty Yellow River Dam. But when it came after Hardrock Hennesey, the tough little mucker summoned the Man of Bronze — the sensational mind who could smash the diabolical forces behind the mind-boggling mystery.
How about that pulp cover? Is that Ham at his dapper best or what? This one is an average Doc at best. The mystery is ineteresting though and the explanation though quick makes sense and the device served the villains purposes. And the location, Yellow River Dam, is a change of pace from exotic civilizations which makes it a nice curve ball in the Doc canon.
This one is significant for me because it re-ignited my interest in Doc Savage after a 20+ year hiatus. In 2003, I was visiting my mom back east and in one of her bookcases, she had my old copy of Tunnel Terror. I read it on the flight home to the west coast, and was once again hooked.