Double Indemnity (1943)

An insurance salesman applies his professional knowledge to a murder scheme and discovers that planning the payout is easier than managing the people involved. Cain makes greed sound practical until its consequences become impossible to price. This is particularly good for the gap between a narrator's persuasive explanation and his actual judgement. Read the novel on its own terms: its characters and details differ from the famous film. Compact, nasty and very efficient.