| Clue | Source | Date |
|---|---|---|
| Billionaire mining magnate, Gina - (8) | ||
| Publisher that merged with Holt and Winston in 1960 | Wall Street Journal | 03 Jun 2023 |
| Mary Roberts --, author of mystery novel 'The Circular Staircase' | The Telegraph General Knowledge | 22 Apr 2019 |
| Miss Pinkerton's creator | ||
| Author of The Circular Staircase. | ||
| "Circular Staircase" author. |