Malice Aforethought is a 1931 crime novel by Anthony Berkeley Cox, writing under the pen name Francis Iles. The story is about a middle-aged country doctor, Dr. Edmund Bickleigh, and his plan to murder his wife, Mrs. Julia Bickleigh. The story begins in 1928 in a small village in Devonshire called Wyvern's Cross.

Bickleigh is married to Julia, a woman who is older and of a higher social status than him. Her domineering manner feeds into his inferiority complex, which he compensates for by having affairs with local women. When his latest fling ends and Julia sneers at him, Bickleigh resolves to silence his wife forever and begins plotting the perfect murder.

As Bickleigh's passion for the mysterious Madeleine Cranmere grows, so does his resolve to murder his wife.