 Chapter titles: 1. An Apartment House Case 2. The Hidden Hands 3.  The Pocket Wireless 4. An Old Grudge 5. On the Rack 6. The Unseen  Terror 7. The House of Mystery 8. The Inherited Sin 9. Lost in  London 10. The Ship of Horror 11. A Desert Vengeance 12. Neath Iron  Wheels 13. Tongues of Flame 14. A Bolt from the Blue 15. The Black  Box