| title | ISBN-13 (ISBN-10) | year of publica- tion | other author(s) |
|---|---|---|---|
| The Secret Service: The Hidden History of an Engimatic Agency | 978-0-7867-1617-3 (0-7867-1617-7) | 2005 | |
| The Secret Service: The Hidden History of an Enigmatic Agency | 978-0-7867-1084-3 (0-7867-1084-5) | 2002 | Peter F. Stevens |