| Ladislas | Aftus | A psychologist in Berlin. Helen's new doctor. |
| Roger | Babson | An American entrepreneur. |
| Mikhail | Bakunin | A Russian revolutionary anarchist. |
| Dr. | Bally | The owner of Medico-Mechanic Institute. |
| Charles | Barney | The President of Knickerbocker Trust Co. |
| Amy | Beach | A composer. |
| Mr. | Betterley | One of Brevoort's close friend. |
| Andew | Bevel | A Manhattan financier. Narrator. |
| Clarence | Bevel | William and Louisa's son. Andrew's grandfather. |
| Edward | Bevel | Tommy and Clarence's son. Andrew's father. |
| Mildred | Bevel | Andrew's wife. |
| William Trevor | Bevel | Andrew's great-grandfather. |
| Ernest | Bloch | A composer. |
| Catherine | Brevoort | Helen's mother. |
| Helen | Brevoort | Benjamin's wife. |
| Leopold | Brevoort | Helen's father. |
| Giordano | Bruno | An Italian philosopher. |
| Pau | Casals | A musician. |
| Grover | Cleveland | Solomon's customer. |
| Miss | Clifford | The Bevel's housekeeper. |
| Grace | Cox | Edward's wife. Andrew's mother. |
| Ruth | Crawford | A composer. |
| Franz | Ferdinand | The archduke. |
| Irving | Fisher | The nation's leading authority on economics. |
| Louisa | Foster | William's wife. |
| Helmut | Frahm | The current director of Medico-Mechanic Institute. |
| Luigi | Galleani | An Italian writer. |
| Arturo | Giovanitti | A poet. |
| Warren | Harding | The current President. |
| Jascha | Heifetz | A violinist. |
| Thomasina | Holbrok | Andrew's grandmother. Clarence's wife. |
| Mary | Howe | A composer. |
| Adelaide | Howland | Mildred's mother. |
| William Zachary | Irving | Solomon's customer. |
| Thomas | Jefferson | The 3rd U.S. President. |
| Prof | Keene | Andrew's math mentor. |
| Fritz | Keisler | A violinist. |
| George Calvert | Leighton | Andrew's architect. |
| Shleldon | Lloyd | Benjamin's most-trusted assistant. |
| Anna | Lopizzo | A mill worker who was killed during the strike. |
| Enrico | Malatesta | One of the founding fathers of Anarchism. |
| Raimund | Mandl | A composer. |
| John Pierpont | Morgan | Solomon's customer. |
| Alexander Dana | Noyes | A journalist. |
| Mrs. | Osgood | One of Brevoort's close friends. |
| Ida | Partenza | Andrew's autobiographer. Aka: Caroline Kincaid, Ida Prentice. |
| Mr. | Prentice | Ida's father. |
| Margaret | Pullman | Brevoort's friend. |
| Lorenz | Rantzau | The man from Haber Pharmaceuticals who wrote to Benjamin. |
| Benjamin | Rask | A legendary Wall Street tycoon. |
| Solomon | Rask | Benjamin's father. A tobacco business owner. |
| Wilhelmina | Rask | Benjamin's mother. |
| Ottorino | Respighi | A composer. |
| Mr. | Shakespear | The man who interviewed Ida. |
| Pleasant | Stovall | U.S. minister to Switzerland. |
| Igor | Stravinsky | A composer. |
| Harold | Vanner | The man who wrote a novel about Mildred. |
| Edgard | Varese | A musician. |
| Shelby | Wallace | One of Helen's friends. |
| Bruno | Walter | The conductor. |
| Woodrow | Wilson | The 28th U.S. President. |
| John | Winslow Jr. | The man who managed Rask's assets. |
| Archie | | One of Andrew's friends. |
| Cager | | One of Andrew's friends. |
| Coolidge | | The former President. |
| Dick | | One of Andrew's friends. |
| Fred | | One of Andrew's friends. |
| Gatti-Casazza | | The general manager of Metropolitan Opera. |
| Jack | | Pierpont's son. |
| Jack | | Ida's boyfriend. |
| Mattia | | Ex-boyfriend of Ida's mother. |
| Maude | | One of Helen's friends. |
| P.Casals | | One of Helen's friends. |
| Paracelsus | | The 1st physician of the spa. |
| Pep | | One of Helen's friends. |
| Pepper | | One of Andrew's friends. |
| Winnie | | One of Helen's friends. |
