The Lady in the Lake is a 1943 detective novel by Raymond Chandler featuring the Los Angeles private investigator Philip Marlowe.

Notable for its removal of Marlowe from his usual Los Angeles environs for much of the book, the novel's complicated plot initially deals with the case of a missing woman in a small mountain town some 80 miles (130 km) from the city.

The book was written shortly after the attack on Pearl Harbor and makes several references to America's recent involvement in World War II.

Kingsley had received a telegram from Crystal about two weeks before stating that she was divorcing him and marrying her gigolo boyfriend, Chris Lavery.

Back at his office, Marlowe finds a note from Kingsley's secretary giving him the address of Dr. Almore's wife's parents.

He wears one of Kingsley’s scarves to the rendezvous, but when he meets Crystal, Marlowe insists that she answer his questions before receiving the money.

Marlowe wakes up stinking of gin and with Crystal lying naked, bloody and strangled to death on the bed.

In the final confrontation at the cabin, Marlowe reveals that the murdered woman in Bay City, assumed to be Crystal Kingsley, was actually Mildred Haviland, killed in a jealous rage by Al Degarmo, who was her former husband.

The murdered woman in Little Fawn Lake, supposed to be Muriel Chess, was actually Crystal Kingsley, killed by Mildred Haviland, who then assumed her identity.

Degarmo attempts to escape but is killed while crossing a dam guarded by wartime sentries under orders to shoot potential saboteurs.

One author comments that the book's title is an explicit reference to the Lady of the Lake, the enchantress of Arthurian romance, especially in making its focus a mysterious female who shifts between roles in different versions of the telling.

Mildred Haviland had disappeared after the killing of Dr Almore’s wife and then married Bill Chess, using the name Muriel; quitting that role, she impersonates Crystal Kingsley at the hotel in San Bernardino; and she throws Marlowe off the scent by introducing herself to him as Mrs Fallbrook, the owner of Chris Lavery’s apartment after his murder.