So my new favorite thing is the Internet Archive—which I found the other day during a random Google search—and, for the moment, particularly Motion Picture Herald, a trade pub aimed at movie theater exhibitors that began in 1931 and lasted until 1972. So in gangster-film terms, from “The Public Enemy” to “The Godfather.” 

A few Warner Bros. ads from 1931 tell the story of the former. The first is from April 4, 1931 about a new movie slated to open in New York on April 23:

Love the shot they use for Cagney. What a mug.

Marketing language is usually horribly incorrect/lies but they weren't off about this. Nothing like it, or Cagney, had ever hit the screen before. They were less correct on “...nothing ever will again!” Success breeds copycats like rabbits. Plus he made movies for another 30 years.

Five weeks later, May 9, the mug was a star, and got a two-page spread:

I love the look of these ads, as well as their oddities. “Nuts” gets quote marks but not Loco? And the hyphenation of “rec-ords”? 

Just a few weeks later, on May 23, as part of a 16-page advertisement trumpeting “35 Outstanding Stars” from Warners' 1931-32 schedule, the studio is already downplaying Cagney's breakout hit for his next picture. That's how fast things moved back then.

In the new one, Cagney will “have a more powerful role than in his ‘Public Enemy.’” He didn't but the movie wasn't bad. Except it wasn't called “Larceny Lane” (they changed it to “Larceny Lovers,” returned to “Larceny Lane,” then at the 11th hour switched it to “Blonde Crazy”) and Marian Marsh wasn't Cagney's co-star (Joan Blondell was). BTW: Someone at Warners must‘ve really liked Marsh, because she’s promo‘ed in two other movies in this ad: “The Mouthpiece” with Warren William, which she also wasn’t in; and “The Other Man” with William Powell, which I think became “The Road to Singapore.” At least she was in that one.

So what happens after a new star lights the firmament? Right, call the lawyers:

“Or in any other occupation whatsoever”? What sweethearts those Warners were.