This is actually based on two Donald Hamilton novels - the one with the same title and also the first in the Matt Helm series, "Death Of A Citizen". From this novel comes the introductory business of Matt Helm returning reluctantly to the world of espionage through the intercession of a woman named Tina. However, it must be stressed that there is very little of either book in this film - the Matt Helm novels are very serious and view the world of espionage coldly as something very unpleasant, whereas the films are ridiculous parodies done in imitation of the James Bond series.

Although one of the greatest female dancers in the history of the movie musical, Cyd Charisse singing in films was almost always dubbed. A young Vikki Carr performed her singing in The Silencers (1966).

The gorgeous statuesque blond stripper in the opening title sequence is dancer Larri Thomas who would later portray Henrietta Hippo on TV's New Zoo Revue in the early 1970s.

In the scene where Matt Helm (Dean Martin) is checking into the Phoenix Hotel and Andreyev (Roger C. Carmel) is lurking in the foreground, the hotel newsstand is immediately behind him. The newsstand shelf is lined with books from Donald Hamilton's Matt Helm series, on which the movie is based.

A Frank Sinatra song (Come Fly With Me) has a cameo in this movie series. It would be followed in The Ambushers (1967) by another Sinatra song - Strangers In the Night. Both songs were always played before or after Dean Martin's song Everybody Loves Somebody Sometime whenever Matt Helm is trying to set a romantic mood with a girl. Also, on both occasions, Martin made fun of those songs (calling Sinatra "terrible" in this movie, and in The Ambushers referring to it as a Perry Como song).

Continuity

One of the guards is shot, and the exit wound can be seen on his back. When he turns toward the camera, before falling, is it seen that there is no corresponding entrance wound.

Helm's car is smashed repeatedly by two other cars and emerges completely unscathed.

In the missile control room near the end, Tung-Tze's submachine gun has no magazine in it when he enters the room, but a magazine is present in a later shot.

In the closeups of the Allied Van Lines truck, the secret viewing ports and upper turret that open up do not match the number or location of those seen in a subsequent medium shot of the same van.

During the car chase, Gail Hendricks can be seen sitting much closer to Matt Helm in the shots inside the car compared to the shots from outside (behind) the car. Also the front seat is significantly different when seen from outside the car. It is a bench seat with headrests.



Factual errors

The rear shot gun bullet doesn't get through the phone book during the test but easily goes through the shooter's body a little later.



Revealing mistakes

When Matt Helm slides off into the bathtub there are already several water stains visible on the sheets, including one where likely he was wearing a swimsuit, already wet from previous takes.

Lovey is seen to be wearing a bra after she supposedly climbed naked from the bath, been dried, and had a bathrobe placed on her.

(at around 1h 31 mins) Optical Special Effects error regarding the Allied Van Lines truck, supposedly with a helicopter inside. When the helicopter appears to be mechanically raised upwards from inside the truck, the incorrect background behind the helicopter of the blue sky and the fluffy white clouds also is raised upwards from inside the truck. When the helicopter flies away, the actual landscape of rocky and sandy hills, is seen behind the Allied Van Lines truck.



Audio/visual unsynchronized

When Matt goes to his wet-bar to make a drink, the sound his hand makes in the ice bucket is of crushed ice, but each time he goes to the glass he drops in cubes.



Crew or equipment visible

The line to the squibs under Kovack's shirt, running down her leg, can be seen for a fraction of a second at the instant she is shot.

(at around 1h 40 mins) Sounds of a still camera autowinder in the ruined control room are heard as Tung-Tse is pointing a machine gun at Gail's head. It is heard several times throughout the scene, whenever the actors seem to strike a photogenic pose.

A camera is visible through the rear window of Matt Helm's station wagon during the car chase scene.