43 books in series

The Hardy Boys Casefiles

The Hardy Boys Casefiles is a 43-book series with 43 released primary works first released in 1983 with contributions by Franklin W. Dixon, Kate William, Jacqueline Carroll, R.L. Stine, and Cathy East Dubowski.

Evil, Inc.
The Lazarus Plot
Deathgame
See No Evil
Brother Against Brother
The Perfect Getaway
The Borgia Dagger
Line of Fire
The Number File
A Killing in the Market
Street Spies
Disaster for Hire
Scene of the Crime
Trouble in the Pipeline
Nowhere to Run
Countdown to Terror
Thick as Thieves
The Deadliest Dare
Without a Trace
Cover 8

Running on Empty

Diplomatic Deceit
Last Laugh
In Self-Defense
Valtapeliä
Uncivil War
Web of Horror
Deep trouble
Cover 8

No Mercy

Sheer Terror
False Alarm
Virtual Villainy
Mission: Mayhem
Against All Odds
Frame-Up
Fast break
Blown away
Moment of Truth
The Hardy Boys Casefiles #112
Clean Sweep
Acting Up
Blood sport
The Last Leap
High-Wire Act
Stress Point #125