Murder & Mayhem is a bookshop specializing in detective fiction in Hay-on-Wye, otherwise know as the UK's town of books. Founded in 1997 by Derek Addyman and Anne Brichto who also have two other bookshops in town, Addyman Books and The Addyman Annexe. Murder & Mayhem is an A to Z of detective fiction, true crime, and horror.

"We have large sections of Green Penguins, Agatha Christie and Sherlock Holmes. This uniquely decorated shop honors the golden age of crime and turn of the century horror."