Note: The reader is referred to the bibliography by Mr. Hulings C. Brown appearing in the Boston Evening Transcript for 5 May 1923. Mr. Brown’s arrangement of the titles is alphabetical (including both English and American titles). His list includes Mr. Oppenheim’s five serials of book length, not given below because not published in book form. Mr. Brown also gives the publisher (except in a few cases where no record exists). In the list below books that have been published in America are starred; those that have been published in America and were recorded by Mr. Brown as in print are double-starred. Books written under the pseudonym “Anthony Partridge” are so indicated.
| 1887 | Expiation |
| 1894 | A Monk of Cruta |
| 1895 | **A Daughter of the Marionis. First title in America was To Win the Love He Sought. |
| 1895 | The Peer and the Woman |
| 1896 | False Evidence |
| 1896 | A Modern Prometheus |
| 1896 | *The Mystery of Mr. Bernard Brown |
| 1896 | The Wooing of Fortune |
| 1897 | The Amazing Judgment |
| 1898 | *As a Man Lives. First title in America was The Yellow House. |
| 1898 | A Daughter of Astrea |
| 1898 | *Mysterious Mr. Sabin |
| 1899 | *Mr. Marx’s Secret |
| 1899 | The Postmaster of Market Deighton |
| 1899 | **The Man and His Kingdom |
| 1900 | *A Millionaire of Yesterday |
| 1900 | *The World’s Great Snare |
| 1901 | **The Survivor |
| 1902 | **A Sleeping Memory |
| In England: The Great Awakening |
| 1902 | *Enoch Strone |
| In England: Master of Men |
| 1903 | *The Traitors |
| 1903 | **A Prince of Sinners |
| 1903 | **The Yellow Crayon |
| 1904 | **Anna the Adventuress |
| 1904 | **The Betrayal |
| 1905 | **A Maker of History |
| 1905 | **The Master Mummer |
| 1906 | *A Lost Leader |
| 1906 | The Tragedy of Andrea |
| 1907 | **The Malefactor |
| In England: Mr. Wingrave, Millionaire |
| 1907 | *Berenice |
| 1908 | *The Avenger |
| In England: The Conspirators |
| 1908 | **The Great Secret |
| In England: The Secret |
| 1908 | *The Distributors, “by Anthony Partridge” |
| In England: Ghosts of Society. Another title in America was The Plunderers |
| 1908 | *Passers-By, “by Anthony Partridge” |
| 1909 | *The Governors |
| 1909 | **The Missioner |
| 1909 | **Jeanne of the Marshes |
| 1909 | *The Kingdom of Earth, “by Anthony Partridge” |
| In England: The Black Watcher |
| 1910 | *The Long Arm of Manister |
| In England: The Long Arm |
| 1910 | **The Illustrious Prince |
| 1910 | **The Lost Ambassador |
| In England: The Missing Delora |
| 1911 | *The Moving Finger |
| In England: A Falling Star |
| 1911 | *The Golden Web, “by Anthony Partridge” |
| 1911 | **Havoc |
| 1912 | **Peter Ruff and the Double Four |
| In England: The Double Four |
| 1912 | **The Lighted Way |
| 1912 | *Those Other Days (short stories) |
| 1912 | *The Court of St. Simon, “by Anthony Partridge” |
| 1913 | **The Mischief Maker |
| 1913 | *For the Queen (short stories) |
| 1913 | Mr. Laxworthy’s Adventures |
| 1913 | **The Tempting of Tavernake |
| In England: The Temptation of Tavernake |
| 1914 | The Amazing Partnership |
| 1914 | *The Double Life of Mr. Alfred Burton |
| 1914 | **The Way of These Women |
| 1915 | *An Amiable Charlatan |
| In England: The Game of Liberty |
| 1915 | **Mr. Grex of Monte Carlo |
| 1915 | *The Black Box |
| 1915 | **A People’s Man |
| 1916 | The Mysteries of the Riviera |
| 1916 | **The Vanished Messenger |
| 1917 | **The Hillman |
| 1917 | **The Kingdom of the Blind |
| 1918 | **The Double Traitor |
| 1918 | **The Cinema Murder |
| In England: The Other Romilly |
| 1918 | **The Pawns Count |
| 1918 | **The Zeppelin’s Passenger |
| In England: Mr. Lessingham Goes Home |
| 1919 | **The Wicked Marquis |
| 1919 | **The Curious Quest |
| 1920 | **The Great Impersonation |
| 1920 | **The Box with the Broken Seals |
| In England: The Strange Case of Mr. Jocelyn Thew |
| 1920 | **The Devil’s Paw |
| 1920 | Aaron Rod, Diviner |
| 1920 | Ambrose Lavendale, Diplomat |
| 1920 | Hon. Algernon Knox, Detective |
| 1921 | **Jacob’s Ladder |
| 1921 | **The Profiteers |
| 1921 | **Nobody’s Man |
| 1922 | **The Great Prince Shan |
| 1922 | **The Evil Shepherd |
| 1923 | **The Seven Conundrums |
| 1923 | **The Mystery Road |
| 1923 | **Michael’s Evil Deeds |
| 1924 | **The Wrath to Come |
| 1924 | **The Passionate Quest |