Lew Harper (Newman) is a rumpled, world-weary detective in the middle of a divorce from his wife Susan (Janet Leigh). His friend Albert Graves (Arthur Hill), an attorney, brings him a job. Albert's client, Ralph Sampson, has disappeared. Samson's embittered ex-wife Elaine (Lauren Bacall) certainly doesn't care if Ralph lives or dies, but hires Harper out of a sense of obligation more than anything else. Sure enough, Samson has been kidnapped. Harper is drawn into a mystery that involves Samson's sexy daughter Miranda, Samson's pilot/flunkie Allan Taggert (Robert Wagner), a drug-addicted nightclub singer named Betty Fraley (Julie Harris), all-around sleazeball Dwight Troy, and Troy's sad alcoholic wife, former actress Fay Estabrook (Shelley Winters).
Based on Ross MacDonald's Lew Archer novel The Moving Target. Newman reprised the Harper role in the 1975 film The Drowning Pool.
- Actor IS the Title Character: Advertised as "Paul Newman is Harper."
- Adaptation Name Change: In the novel, the protagonist was named Lew Archer. The Movie changed his name to Lew Harper because the producers bought the rights to the novel, but not the overall rights to the character.
- Bad to the Last Drop: In the opening scene, Harper, realizing he is out of coffee, makes a cup from yesterday's coffee grounds, which he fishes out of the garbage. Judging by his grimace, the result is not good.
- Briefcase Full of Money: Assembled to carry the $500,000 ransom demand.
- Character Title: Harper features Harper.
- Cold-Blooded Torture: Dwight Troy resorts to burning Betty's feet with a cigarette to make her reveal where the ransom money is hidden.
- Cool Car: Harper drives a Porsche Speedster - as befits the low-rent detective, it's painted a couple shades of primer (and presumably, in the mid-1960s, Speedsters were still affordable for low-rent detectives).
- Detective Drama: Probably a more exciting job for Harper than his usual divorce cases.
- Dirty Old Man: Harper calls Albert this after finding out Albert is in love with Miranda, who is less than half his age.
- Disney Villain Death: Harper's fight with a bad guy in a warehouse that's storing ship anchors ends with the bad guy falling from a catwalk onto the anchors below.
- Driving a Desk: Done horribly, as was usually the case, like the scene in which Harper is driving Miranda along the winding roads of the California coast.
- Establishing Character Moment: A rumpled, disheveled Harper gets up from sleeping on a couch, and makes coffee with yesterday's coffee grounds. The shot then reveals that he's sleeping in his office. Establishes what kind of person Harper is and how his life is going.
- Fille Fatale: Miranda, who has Albert wrapped around her little finger, flirts shamelessly with Albert, and tries to seduce Harper.
- Going by the Matchbook: Harper pulls a matchbook out of the pocket of Eddie, the dead guy who came for the ransom money. It leads him to the nightclub where Betty Fraley is performing.
- The Ghost: Ralph Sampson, millionaire, crook, bad husband, and dirtbag, discussed at length, but never seen alive.
- Instant Death Bullet: Both Dwight Troy and Allen Taggert die instantly after being shot in the torso.
- Lady Drunk: Fay Estabrook seems to spend most of her time getting drunk in bars. Harper refers to her as a "fat alcoholic."
- Left Hanging: In the last scene Alfred confesses, saying he killed Sampson basically on impulse after finding Sampson—a bad person and all-around monster who was thoroughly hated by his daughter Miranda—tied up on the boat where he was left by the kidnappers. Harper says he has to turn Alfred in, whereupon Alfred says he'll have to shoot Harper. Harper gets out of the car, and Alfred pulls his gun. Alfred can't bring himself to shoot Harper, though, saying "Oh hell", and lowering his gun. Harper says "Oh hell" as well, and raises his arms in frustration—freeze frame. The End.
- Let Off by the Detective: Maybe. See Left Hanging above.
- Lens Flare: Produced by a police flashlight after Harper finally calls the cops.
- Match Cut: And a pretty good one. Fay is wobbling on her feet from too much liquor at the bar, only to finally fall down—cut to Fay crumpling onto her couch at home.
- Satellite Love Interest: Susan basically exists to give Harper something to feel bad about, and to provide a booty call in one scene.
- Soft Glass: No injuries for Harper after jumping through a glass window to escape a Mook.
- We Have the Keys: Allan and Harper have arrived at a house where they think the bad guys are. Allan, who is getting way too enthusiastic about helping in the private detective game, asks if he can knock the door down. He rams the door with one shoulder, and fails. Wincing in pain, he rams the door with his other shoulder, and fails. As he cringes from two hurt shoulders, Harper laughs, and opens the door, which wasn't locked.
- Wicked Stepmother: Elaine and Miranda hate the hell out of each other. Miranda accuses her stepmother of faking her paralysis. Elaine's face shines with malevolent glee when she's about to tell Miranda that her father is dead.