The mystery genre is not just about detective fiction.
Yes, there are a few classic detective novels in this list, but you'll find a whole lot of different styles of books here - all of them containing some sort of mystery and suspense.

Colony - Jan-Andrew Henderson
Thyla - Kate Gordon
The Golden Day - Ursula Dubosarsky
The Dead I Know - Scot Gardner
Midnight in a Perfect Life - Michael Collins
The House on the Strand - Daphne du Maurier
The Understudy's Revenge - Sophie Masson
Hickory Dickory Dock - Agatha Christie
The Body in the Library - Agatha Christie
Daddy's Little Girl - Mary Higgins Clark
Ordeal by Innocence - Agatha Christie
Mean Spirits - Meg Cabot
Mice - Gordon Reece
The Man in the Picture: A Ghost Story - Susan Hill
The Island - Sarah Singleton
Trash - Andrew Mulligan
The Ruby in the Smoke - Philip Pullman
The Innocents - Nette Hilton
Five Parts Dead - Tim Pegler
The Rembrandt Affair - Daniel Silva
Heart and Minds - Amanda Craig
The Gallagher Girls series - Ally Carter
Heist Society - Ally Carter
Murder in Montparnasse - Kerry GreenwoodA Painted House - John Grisham
Feather Boy - Nicky Singer
The Red Cardigan - J.C.Burke
The Hound of the Baskervilles - Arthur Conan Doyle
Simisola - Ruth Rendell
Death on the Nile - Agatha Christie
The Three-Pronged Dagger - Kerry Greenwood
Killer Plot - Ian Bone
Set in Darkness - Ian Rankin
Missing - Catherine MacPhail
Princes - Sonya Hartnett
The Devil's Own - Deborah Lisson
Murder on the Orient Express - Agatha Christie
Shroud for a Nightingale - P. D. James
The Survivor - Thomas Keneally
Picnic at Hanging Rock - Joan Lindsay
Spider Mansion - Caroline MacDonald
Detective Stories - Phillip Pullman
The Silence of the Lambs - Thomas Harris
Witch Banks - Catherine Jinks
The Japanese Job - Peter Corris
The Flower Net - Lisa See
See How They Run - David McRobbie
The Da Vinci Code - Dan Brown
Disordered Minds - Minette Walters
The Secret History - Donna Tartt
The Rose Queen - M. E. Rabb
Doctored Evidence - Donna Leon
Cruel and Unusual - Patricia Cornwell
The Street Lawyer - John Grisham
A Time To Kill - John Grisham
Something Wicked - Jennifer Rowe
The Photograph - Penelope Lively
Dark Horse - Tami Hoag
A New Kind of Dreaming - Anthony Eaton
The No. 1 Ladies' Detective Agency - Alexander McCall Smith
Through the Tiger's Eye - Kerrie O'Connor
Angels and Demons - Dan Brown
Second Glance - Jodi Picoult
Shakespeare's Secret - elise Broach
Falling From Grace - Jane Godwin
Double Exposure - Brian Caswell
On the Jellicoe Road - Melina Marchetta
Lilies for Love - Felicity Pullman
Out of the Shadows - Carol Hedges
Hit - Tara Moss
The Case of the Diamond Shadow - Sophie Masson
Jigsaw - Garry Kilworth
Murderer's Thumb - Beth Montgomery
The Strange Case of Dr Jekyll and Mr Hyde - Robert Louis Stevenson
The Adoration of Jenna Fox - Mary E. Pearson
Paper Towns - John Green
The Girl with the Dragon Tattoo - Stieg Larson
Unbelievable - Sara Shepard
The Lost Symbol - Dan Brown
The Face on the Milk Carton - Caroline B. Cooney