The Hardy Boys and Tom Swift Ultra Thriller
Also in series {{s|The Hardy Boys}}.
Published in paperback only.
TomSwift.net covers this crossover series along with the contemporary fourth Tom Swift series ({{s|Tom Swift [3]}}) and notes that its content is closer to Tom Swift, although it is credited to Franklin W. Dixon, pseudonymous author of The Hardy Boys.
Titles (2)
| # | Title | Author(s) | Year | Type |
|---|---|---|---|---|
| 1 | Time Bomb | Franklin W. Dixon | 1992 | |
| 2 | The Alien Factor | Franklin W. Dixon | 1993 |