Screenwriter William Goldman has claimed that Paul Newman agreed to do Harper, the film that established the grateful writer's career, only because he was working unhappily on Lady L. (1965) in Europe, and was looking for something as unlike that film as possible. He stars as Lew Harper, a hip L.A. private dick whose business has gotten so bad that he's re-using his coffee grounds. At the suggestion of his friend, attorney Albert Graves (Arthur Hill), the detective takes on the investigation of the disappearance of the wealthy husband of waspish cripple Elaine Sampson (Lauren Bacall). After finding a photograph of former actress Fay Estabrook (Shelley Winters), Harper locates the alcoholic actress in a bar, plies her with booze, and takes her home to search her apartment while she's unconscious. There he takes a call which leads him to another bar to meet Betty Fraley (Julie Harris), a singer with a heroin problem. To curtail his inquisitive behavior, some large and unpleasant gentleman beat him up outside the saloon. Hoping for sympathy from his soon to be ex-wife (Janet Leigh), who has just filed divorce papers, the weary detective is much more successful than he has any right to expect.
~ Michael Costello, All Movie Guide