• The Missing MinisterTerence Copley
• The Missing Money MysteryCarolyn Keene, Franklin W. Dixon
• The Missing Rock Star CaperR. Parker McVey
• The Mona Lisa is Missing!Ramsey Montgomery
• The Money SpiderRobin Waterfield, Wilfred Davies
• The Monster FamilyR.G. Austin
• The Monster MakerGareth P. Jones
• The Monumental DiscoveryMark Oestreicher
• The Most Amazing Amusement Park in the WorldAnne E. Schraff
• The Movie MysterySusan Saunders
• The Mummy Who Wouldn't DieE.A.M. Jakab
• The Mummy's TombStephanie Spinner
• The Mysterious Old ChurchNeil S. Wilson
• The Mysterious Silence of ScribblesMandy Archer
• The Mystery GuestKaren King
• The Mystery of AtlantisJim Gasperini
• The Mystery of Chimney RockEdward Packard
• The Mystery of DraculaDane Barrett
• The Mystery of Echo LodgeLouise Munro Foley
• The Mystery of Mayhem MansionMatthew K. Manning
• The Mystery of the Aztec TombLaurie S. Sutton
• The Mystery of the Highland CrestLouise Munro Foley
• The Mystery of the Maze MonsterJohn Sazaklis
• The Mystery of the Missing MummyKate McMullan
• The Mystery of the Turkish TattooRose Estes
• The Mystery of Ura SenkeShannon Gilligan
• The Mystery of WitchhavenDaniel Howard, Deborah D’Antonio L. B. Almeida, Kai Wloka
• The Mystery Squad and Mr. MidnightMartin Waddell
• The Mystery Squad and the Artful DodgerMartin Waddell
• The Mystery Squad and the Candid CameraMartin Waddell
• The Mystery Squad and the Cannonball KidMartin Waddell
• The Mystery Squad and the Creeping CastleMartin Waddell
• The Mystery Squad and the Dead Man's MessageMartin Waddell
• The Mystery Squad and the Robots' RevengeMartin Waddell
• The Mystery Squad and the Whistling TeethMartin Waddell
• The Nameless CityGiny Valrís
• The NastyGraeme Davis
• The OblivionatiJoe Cheal
• The OfficeJilly Gagnon, Mike MacDonald
• The Omega RebellionTroy Denning
• The Omega ZoneJoe Dever
• The Option PlayBob Darden
• The OrbGraeme Davis
• The Orchid of LifeDavid Brunskill
• The Oregon TrailMatt Doeden
• The Organization GameCraig Hickman
• The Other Side of the HudsonKenneth Roseman
• The OutbackTracey West
• The Overnight OrdealKaren Ball
• The Owl TreeR.A. Montgomery
• The Perfect PlanetEdward Packard
• The Phantom SelfVictoria Hancox
• The Phantom SubmarineRichard Brightfield
• The Pillars of the SkyDave Morris
• The Pirate HouseAnne E. Schraff
• The Pirate's CurseAdam Blade
• The Pit of DarknessMartin Charbonneau
• The Plague Lords of RuelJoe Dever
• The Plains of Howling DarknessDave Morris, Jamie Thomson
• The Planet EaterEdward Packard