Which Stephen King novel won the 2015 Edgar Award for Best Novel?

The Stephen King novel that won the 2015 Edgar Award for Best Novel was Mr. Mercedes.

Published in 2014, Mr. Mercedes is King's first hard-boiled detective novel. It follows retired police detective Bill Hodges, who is drawn back into a case involving Brady Hartsfield, the criminal known as the Mercedes Killer. The title refers to the stolen Mercedes used in a deadly attack on a crowd seeking jobs.

The Edgar Award is presented by the Mystery Writers of America and honors excellence in mystery and crime writing. Although King is most closely associated with horror, Mr. Mercedes demonstrated his ability to write a tightly constructed crime thriller without relying primarily on supernatural elements.

Readers sometimes confuse this award with the novel's publication year or with the later Bill Hodges books. Finders Keepers followed in 2015, and End of Watch completed the trilogy in 2016, but only Mr. Mercedes won the 2015 Edgar for Best Novel.