| Series |
Years |
Nos. |
Notes |
| Original Hardcovers |
1930–1979 |
#1–56 |
The Original Series; 1930 - 1956 Original Series with 25-chapters (#1-34); 1959 - 1979 revisions and new 20-chapter books (#1-56) |
| Paperback Digests |
1979–2003 |
#57–175 |
Paperbacks from Simon & Schuster imprints Wanderer, Minstrel, and Aladdin. |
| Be a Detective |
1984–1985 |
#1–6 |
Choose-your-own-adventure type series with The Hardy Boys. |
| Files |
1986–1997 |
#1–124 |
YA tone; higher stakes (murders!), romance, and very 1980s-1990s. |
| Super Mysteries |
1988–1998 |
#1–36 |
Nancy + Hardy Boys crossovers. |
| Notebooks |
1994–2005 |
#1–69 |
Younger readers; relaunched later as Clue Crew. |
| On Campus |
1995–1998 |
#1–25 |
College-era spin-off; Big Departure, Romance. |
| Girl Detective |
2004–2012 |
#1–47 |
First-person reboot; some trilogy arcs. |
| Clue Crew |
2006–2015 |
#1-40 |
Successor to the Notebooks; Chapter-book line; replaced by Clue Book. |
| Super Mysteries '07 |
2006–2015 |
#1-40 |
Nancy + Hardy Boys crossovers; modern version |
| Diaries |
2013–Present |
1–26+* |
Current main series (ongoing). Book #27 coming out January 2026. |
| Clue Book |
2015–2024 |
#1–19 |
Chapter-book successor to Clue Crew. |
| Comics / Graphic Novels |
Various |
— |
Papercutz, Dynamite, others. |
| Other Spinoffs |
Various |
— |
Board Books, SuperSleuths, Campfire Stories, etc. |