I enjoyed it. But I was puzzled by King's description of the book as his first detective novel. He wrote an excellent novella about 8 or 9 years ago called "The Colorado Kid" for the Hard Case Crime series. I thought it was great. Same goes for "Joyland," which came out last year.

But then again, both of those books were very short by King's standards. So it's possible that he meant that "Mr. Mercedes" was his first full length crime novel.