Popular Library 87 (1947)
The humming noise of the automatic elevator stopped and the hall porter glanced idly toward the bronze doors.
Twenty minutes later, when no one had emerged, the porter became uneasy and forced the doors open. Inside he found Sir Ernest Tallant, dead! Shot through the heart in a hermetically sealed elevator! It looked like the perfect crime - until Dr. Horatio Glass, in his blundering way, set Inspector Hornbeam on the track of the one crucial clue.
Two famous detective story writers combine their masterly talents in this baffling and suspenseful mystery novel.