I was talking about this with a friend and I could only seriously come up with one book that would qualify as the best mystery of the decade: Gone Girl by Gillian Flynn. And it didn't even win the Edgar in its year.
Are there any others that would make the short list?
P.S.
For those who haven't read the book or seen the movie already, it's one of those books that is very difficult to read about without seeing the plot spoiled, so just read it!
GONE GIRL would definitely make my Top Ten mysteries of the decade, too. I've read so many mysteries (as I'm sure you have, too) that it's hard to remember all of them. Off the top of my head, I can come up with a few favorites:
TRUST ME by Hank Phillippi Ryan
THE SILENT GIRL by Tess Gerritsen
DARK MATTER by Blake Crouch
THE WOMAN IN CABIN 10 by Ruth Ware
THINK OF A NUMBER by John Verdon
TRUST YOUR EYES by Linwood Barclay
WHAT THE DEAD KNOW by Laura Lippman
THE WITCH ELM by Tana French
THE WIFE by Alafair Burke
THE SECRET SISTER by Brenda Novak
TELL NO ONE by Harlan Coben (Had to check when this was published - 2001, so it was in the past decade.)
All of the Three Pines mysteries by Louise Penny (since they all link, it's hard to pick a favorite)
Well, that's a bunch and I haven't even found a methodical way of tracking the books I've read in the 21st century. I used to keep a list on Shelfari and Barnes & Noble, but those list both vanished into the ether. I can track the library books I've checked out but I only joined the library about a year ago. I know I'm forgetting lots of great books.
I'm eager to find out YOUR favorites!