A rock pool with a deadly secret. A bank holiday heatwave dominated by the murder of an unknown man. A sun-drenched picnic that ends in a sinister locked-room mystery. And an Adriatic holiday interrupted by a beautiful couple ... who aren't quite who they seem to be. All these, and many more, can be found in these classic stories of summertime murder and mayhem, featuring masters of the genre from Dorothy L. Sayers to Arthur Conan Doyle. From St Mark's Square in Venice to the English seaside, their tales will puzzle, entertain and prove that - no matter how far you travel - there's no rest for the wicked. Selected by Cecily Gayford