Everyone knows the sound of that introduction, the nine tones by horns, which in the radio show is even more impressive sounding than the TV version. The narrator's flat tones indicate the veracity of the story and off we go for another show about a police investigation.
I never paid attention to this as a kid when Dragnet was on TV, but Sgt Friday was never a detective in any one branch. He would hop around to vice, homicide, juvenile, wherever the story required. Because unlike most cop shows, Dragnet wasn't a story about character, it was a story about a case with a regular cast that reoccurred.
So Joe Friday would be in whatever branch the story required, because although there were bits of slowly revealed information about the man's life (he was single, lived with his mom, had been in the war, etc), the characters were incidental. What mattered was the case, and the procedures taken to bring it to trial.
This is a pretty unique approach to storytelling, where the characters are not fixed or stable, but move around and are in whatever situation is required to tell the story. If the case is about a missing kid or troublemaking teens, then the main characters are in Juvenile department. If its about drugs or rape, they are in vice. Ordinary police don't hop around like that, they tend to stay in a department and specialize, moving on occasion to change their setting. Like all jobs, you get a department and stay there.
And that means the focus of every show is on the case and how it gets done, not the characters and how they do it. The radio show especially was kept in these terms, even though there were regular names and people.
For example, the original chief of detectives was Ed Backstrand, but after about a year, he retired (with a retirement celebration and speech) and another man took over, named Thad Brown. What was interesting is that many of the people in Dragnet were based on real folks in the LAPD (such as Thad Brown). But these characters in place were more a setting than characters, they were in place to build a framework of veracity which the show was hung on.
Great pains were taken to make the show not only as true to life as possible, but as ordinary and normal as possible. The intent was to make cops real people, not too sympathetic, not scary or tough, not too heroic, but just folks. Little details like inlaws coming to stay at a cop's house or how bad the coffee is at a shop were dropped in, not to develop the characters, but to enhance the truth of the setting.
Each show feels more like you've dropped into an actual event than a radio show. That's why the deliveries were so flat, to deliberately avoid dramatic readings, to make them seem real and believable rather than exciting. Over time, this effect got a little too strong, and they became wooden instead of plausible. But the radio show has real power.
What's interesting is that while the idea of a procedural drama wasn't entirely new, Dragnet made it an art form and something fresh to the public. The idea for Dragnet came from a noir film called He Walked By Night which you can watch for free online if you want. Jack Webb was in that movie, and the film has a real documentary procedural feel to it that's very familiar to Dragnet viewers. Its a good movie, by the way.
Joe Friday's partner on the radio show was Ben Romero, a sort of Texan fellow with a bit of a drawl who was a good equal to Friday. Although Friday is the main character, Romero is no sidekick and I have wondered for a while why they changed his character for the TV show. Well, it turns out that Romero's actor died of a heart attack, so they dramatized that for the show and had Romero die, too.
Dragnet's gritty tone and events were run later at night, after the kids were put to bed. They were careful around some topics, not as gruesome and shocking as cop shows today (no cut apart bodies, no closeups of stab wounds), but the writers did not shy away from hard subjects.
While the second TV series of Dragnet became preachy and featured long monologues by Friday and other characters on moral and legal topics, the radio show was straight cop drama. Every once in a while you'd get a one liner about something, foreshadowing later Jack Webb soap boxes, but they were very minimal and fit the show.
Don't get me wrong, a lot of those TV show speeches were quite good. Jack Webb would tear apart the counterculture's methods and mistakes, while supporting their complaints and some of their motivations. He could see the same problems they could, but saw problems they could not. Its just that the show lost its direction as a police procedural and that's too bad.
Dragnet portrayed cops differently than any show before it. Most radio shows had cops as idiots (for the detectives to outshine) thugs and brutes, or super heroes who did no wrong. Dragnet instead showed them as a variety of human beings doing a job. Scenes were underplayed rather than dramatized, to make each seem more real ("as real as a guy pouring a cup of coffee" is how Webb put it).
Many details such as how interrogations are carried out and devices cops used to put criminals at ease and get them to talk are old hat now, but Dragnet was introducing many of them for the first time. Back in the 50s when this show ran, people had never really had any experience with how cops worked, and it was all new.
What's interesting is that the people being questioned almost never get a lawyer around to help them, which probably was common then; lawyers are expensive, much less common then, and the Miranda ruling wasn't until the 60s. Cops never beat a confession out of anyone, but they almost always managed to get one in these stories, using tried and true techniques and evidence.
What's interesting is that the crime lab was around then, and they processed scenes and evidence CSI-style. Fingerprints, hairs, footprints, all sorts of evidence were available and used by the police. They didn't have Mass Spectrometers and DNA analysis, but they had almost everything else - most of those tricks used on CSI have been around a long time, even if the machines used to make it easier in the shows are fairly new.
All in all, I recommend Dragnet pretty highly. It is consistently entertaining, intelligent, and interesting. There's a reason this show became such a cultural icon, so much so that to this day aspects of the show such as its introduction and "just the facts" are recognized and used by people who were born decades after it was off the air.
Just avoid that horrible 1987 movie version that tried to turn the TV show into a spoof and was an almost total failure in the process. Interestingly enough, Joe never has said "just the facts, ma'am" on the radio show yet, and I'm several years into it.
Incidentally, that song played for the intro is called "Danger Ahead" and it was originally in a 1946 film entitled The Killers.