| Julius | Arbor | The American collector. |
| Dr. | Benedict | The chief-of-staff in charge of the army hospital. |
| Laura | Bitton | William's sister-in-law. Lester's wife. |
| Lester | Bitton | William's brother. |
| Sheila | Bitton | William's daughter. |
| William | Bitton | The book collector. The owner of the stolen manuscript. |
| John | Bronlow | One of Dalrye's colleagues. |
| Robert | Dalrye | General Mason's secretary. Aka: Bob. |
| Robert | Devereux | Earl of Essex. |
| Philip | Driscoll | William's nephew. A news reporter. |
| Gideon | Fell | Protagonist. Doctor of Philosophy, expert on crime. |
| Leonard | Haldyne | The keeper of the jewel house. |
| Ian | Hamilton | A General. |
| Prof. | Hervey | The leading authorities on Poe. |
| Mr. | Hobbes | The Bitton's butler. |
| Amanda Georgette | Larkin | One of the tower's visitors. Philip's neighbor. Aka: Amanda Leeds, Georgie Simpson, Emmy. |
| The | Mad Hatter | The Hat thief. |
| Theopilus | Marks | William's valet. |
| General | Mason | William's friend. The deputy governor of London. |
| Dr. | Masters | The Philadelphia collector. |
| Joseph | McCartney | The owner of the property where Poe's manuscript was found. |
| James | McGuire | A police constable. |
| Edgar Allan | Poe | A famous poet. |
| Mr. | Radburn | The chief warden. |
| Tad | Rampol | Fell's companion. |
| Dr. | Robertson | The leading authorities on Poe. |
| Lord | Sandival | Mark's former employer. |
| Isaac | Simonides-Levy | A well-known member of the stock exchange. |
| Thomas | Sparkle | The police constable. |
| Daniel | Spengler | Julius's friend. |
| Mrs. | Spengler | Mr. Spengler's wife. |
| Dorothy | Starbeth | Martin's sister. Rampole's girlfriend. |
| Martin | Starbeth | Murdered. |
| Mary | Tudor | Philip II's wife. |
| Doctor | Watson | The police surgeon. |
| Allen | | The leading authorities on Poe. |
| Anders | | The police sergeant. |
| Betts | | The police sergeant. |
| Hadley | | The chief inspector. |
| Hamper | | A police sergeant. |
| Jennifer | | The horse. |
| Margaret | | Sheila's friend. |
| Mary | | The mystery woman. |
| Parker | | One of General Mason's assistants. |
| Philip II | | King of Spain. |
| Somers | | The man who investigated Larkin. |
| Sylvia | | Dorothy's former schoolmate. |
