Star Wars and Godfathers and infinite Marvel adaptations are all well and good. But for some of us, this is the only film series that ever really mattered.

Based on the final novel by Dashiell Hammett – the hard-drinking, Communist-supporting ex-Pinkerton detective who revolutionised American literature with his stripped-bare crime stories of the 1920s and ’30s –  the original Thin Man appeared in 1934. Shot in two weeks by director WS Van Dyke it was another crime movie, but it was something else, too: the greatest portrait of (happy) marriage ever put on film.

The detective is Nick Charles (William Powell) – a retired detective, to be precise, a suave gumshoe legend who has given up sleuthing in San Francisco to devote himself to his fabulous, fabulously wealthy, new wife, Nora (Myrna Loy), and all her money. And drinking. Lots of that. It’s Christmas, and, with their fantastic terrier, Asta, they’re honeymooning in snowy Manhattan, but the vacation is interrupted when Nick’s old pal, an inventor, goes missing and his daughter begs him to investigate. Nick can’t be bothered, but Nora, keen for adventure, pesters him into it.

The mystery is quite incomprehensibly convoluted, but here’s the revolutionary thing: it doesn’t matter. Such mundanities as logic, narrative and murder fade away as Powell and Loy spark off each other. The movie is concerned solely with being a movie, with watching these two splendid people being splendid together in splendid surroundings. You could call it proto-post-modern, if you wanted to spoil it.

Powell and Loy banter and jibe constantly, sharp screwball smalltalk, dialogue-dancing like Fred and Ginger. “I read you were shot five times in the tabloids,” she says. “Not true,” he replies. “He didn’t come anywhere near my tabloids.” They walk the sidewalks, pausing strangely at every tree and fire hydrant as, you realise, beneath the frame, Asta stops to do his business.

Did someone mention alcohol? The Thin Man runs on booze. First time we meet Nick, he’s teaching a bartender to mix drinks: “A dry martini, you always shake to waltz time.” Nora arrives and asks how many he’s had. “This will make six.” She takes his and orders herself five more to catch up.

American audiences, just out of Prohibition, still sheltering from Depression, fell in love. The film’s phenomenal success saw Van Dyke helm three sequels, refining the cocktail: After the Thin Man (1936, based on an original story by Hammett), with a young James Stewart acting suspicious; Another Thin Man (1939, also based on an original treatment by Hammett – his last direct involvement with the movie series, and, indeed, his last long piece of fiction writing), introducing Nick and Nora’s baby, Nick Jr; Shadow of the Thin Man (1941), bad business at the race track involving future Actors Studio legend Stella Adler.

Times changed. Ever-tightening censorship saw the tides of liquor begin to dry up, but the Powell-Loy chemistry remained intoxicating. Van Dyke committed suicide in 1943. It didn’t stop the party. They returned for The Thin Man Goes Home (1944), Nick introducing Nora to his disapproving smalltown parents, and Song of the Thin Man (1947), light noir in a smoky jazz underworld, with an 11-year-old Dean Stockwell as Nick, Jr.

It ended there, with Nick and Nora heading off to bed, looking a little tired. But still fabulous. Down the years, there have been many attempts to replicate the magic mixture. But no one will ever match Powell and Loy’s urbane oddball highball. Waltz time, see. That’s the secret.