You got to hand it to Variety for their eye-catching and funny headlines, titles, and phrasing. They christened ‘The Son of Frankenstein” with the moniker – BOO, JR which at once encapsulated and entertained.
In its January 4 edition, it announced:
Hollywood Jan 1 
‘Son of Frankenstein’ completed Saturday (31) at Universal, goes into national release Jan
13 with heavier advance bookings than any other U feature.
Cutters kept pace with the shooting schedule to speed up the distribution.”
There is an excellent reason that Universal garnered “heavier advance bookings” than usual. Back in the spring and summer of 1938, when a dearth of product hit the theaters, an enterprising theater manager (Emil Uman at the Regina Theater in Beverly Hills) put together a triple bill of older films for his venue.
The unspooling of “Dracula,” “Frankenstein,” and “Son of Kong” caused the cops to be called out to control the crowds. Word spread and soon other theaters were looking to book the reissues. Universal gladly offered their titles “Dracula” and “Frankenstein,” as a stand alone double bill (Kong, both original and Son were RKO properties – I’m sure Universal did not want to share the film rentals). And the crowds – and the cops – were repeated – from San Francisco to Boston. Initial short bookings were held over, in some instances, multiple weeks (Philadelphia ran seven). St Louis packed in over 34,000 people in the first three days.
Such business was a bellwether indication that the horror genre was ready for a new installment. Thus, Universal decided to take the money coming in from the revivals and make a sequel. By October 1938 they were negotiating for talent. Boris Karloff took another turn in the monster role; and Bela Lugosi lurked menacingly as the murderous deranged cripple. Willis Cooper, a writer for radio horror programs and three Mr Moto films at Fox, was tapped for the scripting chores. By the 18th the cameras were turning, but not without a few hiccups. No director was listed for the first day of shooting (a role filled soon after by Rowland V Lee), and a principal actor (Peter Lorre) announced for the title roll dropped out. He was replaced on the 24th by Basil Rathbone.
It was given an ‘A’ picture status – better production values, sets, costumes etc., and shoehorned into the few available soundstages at Universal. (Their ‘B’ lineup, judged to be ahead of schedule for upcoming release, caused others of the same designation to be put on hold, freeing up stage space for the ‘A’s). Another ‘A’ production at Universal at the same time was the W. C. Fields vehicle, “You Can’t Cheat an Honest Man.”
I recently watched the film online and enjoyed it despite its predictability and formulaic writing. The atmosphere was fittingly dark and foreboding. And it wasn’t too far along when I realized that Mel Brooks must have used the plot as a template for his “Young Frankenstein.” Here too the son of the monster creator was returning to the scene of his father’s ‘crime.’ The clincher was the local police inspector, played by Lionel Atwill. The character sports an artificial arm, which Kenneth Mars spoofs in Brooks’ version. The only thing is, Mars wasn’t all that far off of what Atwill had done in his characterization, even down to using the wooden arm when striking a light and while using darts.
A viewing is worthwhile just for the comparison.