The Lake of Darkness

Blurb

The Lake of Darkness is a novel by British writer Ruth Rendell, first published in 1980. It won the Arts Council National Book Award for Genre Fiction in 1981.
The title comes from a quotation from Shakespeare's King Lear:
"Frateretto calls me; and tells me Nero is an angler in the lake of darkness. Pray, innocent, and beware the foul fiend".