Stephen King is genius--that's all there really is to it. Mr. Mercedes is a thrilling, sometimes gross, sometimes heartfelt, definitely scary adventure into the minds of both Det. Ret. Hodges and the Mercedes Killer, Brady Hartsfield. Hodges is the quintessential retired detective who wants so badly to solve the case of the Mercedes Killer, who ran into a crowd of jobseekers at a job fair with a Mercedes and drove away unscathed. Now, Mr. Mercedes has contacted Hodges and wants to play a game with him.... 
 I like that readers got both characters' points of view, including Brady's. His sections were sometimes hard to get through (I don't know how King writes this stuff...) but the character himself was totally fascinating. 
 HIGHLY recommended for anyone who's even a little interested in thrillers/crime/mystery novels :).