Som allerede nevnt mistet Grosset & Dunlap rettighetene til å gi ut Hardy-bøker i USA i 1979.

Forlaget Simon & Schuster overtok, og fortsatte å gi fram til 2005 - da den 190. og siste boka kom ut.

Mange Hardy-fans mener at Digest-utgivelsene, som de kalles, ikke kan regnes som en del av kanon. Andre mener at bøkene som er skrevet av de «tradisjonelle» forfatterne (flere av skyggeforfatterne fra de første 58 bøkene fortsatte å skrive Hardy-bøker for Simon & Schuster) også bør regnes med i kanon.

De aller fleste er imidlertid enige om at kvaliteten på serien sank med årene, og seriens død i 2005 kom etter svake salgstall.

Digest-bøkene ble nummerert som en fortsettelse av Grosset & Dunlap-bøkene, og første bok ut i serien er derfor fått nummer 59.

Liste over The Hardy Boys Mystery Stories (Digests):
# 59 Night of the Werewolf
# 60 Mystery of the Samurai Sword
# 61 The Pentagon Spy
# 62 The Apeman's Secret
# 63 The Mummy Case
# 64 Mystery of Smugglers Cove
# 65 The Stone Idol
# 66 The Vanishing Thieves
# 67 The Outlaw's Silver
# 68 The Submarine Caper (Utgitt på nytt som «Deadly Chase»)
# 69 The Four-Headed Dragon
# 70 The Infinity Clue
# 71 Track of the Zombie
# 72 The Voodoo Plot
# 73 The Billion Dollar Ransom
# 74 Tic-Tac-Terror
# 75 Trapped at Sea
# 76 Game Plan for Disaster
# 77 The Crimson Flame
# 78 Cave-In
# 79 Sky Sabotage
# 80 The Roaring River Mystery
# 81 The Demon's Den
# 82 The Blackwing Puzzle
# 83 The Swamp Monster
# 84 Revenge of the Desert Phantom
# 85 The Skyfire Puzzle
# 86 The Mystery of the Silver Star
# 87 Program for Destruction
# 88 Tricky Business
# 89 The Sky Blue Frame
# 90 Danger on the Diamond
# 91 Shield of Fear
# 92 The Shadow Killers
# 93 The Serpent's Tooth Mystery
# 94 Breakdown in Axeblade
# 95 Danger on the Air
# 96 Wipeout
# 97 Cast of Criminals
# 98 Spark of Suspicion
# 99 Dungeon of Doom
# 100 The Secret of the Island Treasure
# 101 The Money Hunt
# 102 Terminal Shock
# 103 The Million-Dollar Nightmare
# 104 Tricks of the Trade
# 105 The Smoke Screen Mystery
# 106 Attack of the Video Villains
# 107 Panic on Gull Island
# 108 Fear on Wheels
# 109 The Prime-Time Crime
# 110 The Secret of Sigma Seven
# 111 Three-Ring Terror
# 112 The Demolition Mission
# 113 Radical Moves
# 114 The Case of the Counterfeit Criminals
# 115 Sabotage at Sports City
# 116 Rock 'n' Roll Renegades
# 117 The Baseball Card Conspiracy
# 118 Danger in the Fourth Dimension
# 119 Trouble at Coyote Canyon
# 120 The Case of the Cosmic Kidnapping
# 121 The Mystery in the Old Mine
# 122 Carnival of Crime
# 123 The Robot's Revenge
# 124 Mystery with a Dangerous Beat
# 125 Mystery on Makatunk Island
# 126 Racing to Disaster
# 127 Reel Thrills
# 128 Day of the Dinosaur
# 129 The Treasure at Dolphin Bay
# 130 Sidetracked to Danger
# 131 Crusade of the Flaming Sword
# 132 Maximum Challenge
# 133 Crime in the Kennel
# 134 Cross-Country Crime
# 135 The Hypersonic Secret
# 136 The Cold Cash Caper
# 137 High-Speed Showdown
# 138 The Alaskan Adventure
# 139 The Search for the Snow Leopard
# 140 Slam Dunk Sabotage
# 141 The Desert Thieves
# 142 Lost in Gator Swamp
# 143 The Giant Rat of Sumatra
# 144 The Secret of Skeleton Reef
# 145 Terror at High Tide
# 146 The Mark of the Blue Tattoo
# 147 Trial and Terror
# 148 The Ice-Cold Case
# 149 The Chase for the Mystery Twister
# 150 The Crisscross Crime
# 151 The Rocky Road to Revenge
# 152 Danger in the Extreme
# 153 Eye On Crime
# 154 The Caribbean Cruise Caper
# 155 The Hunt for the Four Brothers
# 156 A Will to Survive
# 157 The Lure of the Italian Treasure
# 158 The London Deception
# 159 Daredevils
# 160 A Game Called Chaos
# 161 Training for Trouble
# 162 The End of the Trail
# 163 The Spy that Never Lies
# 164 Skin & Bones
# 165 Crime in the Cards
# 166 Past and Present Danger
# 167 Trouble Times Two
# 168 The Castle Conundrum
# 169 Ghost of a Chance
# 170 Kickoff to Danger
# 171 The Test Case
# 172 Trouble in Warp Space
# 173 Speed Times Five
# 174 Hide-and-Sneak
# 175 Trick-or-Trouble
# 176 In Plane Sight
# 177 The Case of the Psychic's Vision
# 178 The Mystery of the Black Rhino
# 179 Passport to Danger
# 180 Typhoon Island
# 181 Double Jeopardy
# 182 The Secret of the Soldier's Gold
# 183 Warehouse Rumble
# 184 The Dangerous Transmission
# 185 Wreck and Roll
# 186 Hidden Mountain
# 187 No Way Out
# 188 Farming Fear
# 189 One False Step
# 190 Motocross Madness