"The Darkness Before Tomorrow" is a 1962 science-fiction novel by Robert Moore Williams, published as one-half of an Ace Double along with "The Ladder in the Sky" by "Keith Woodcott". "The Darkness Before Tomorrow" is a 120 page novel set in the near future of 1980. In many ways, it resembles another novel by Williams that I read previously, "Flight From Yesterday".
In the world of 1980 Los Angeles, scientist George Gillian stumbles upon two dead bodies in quick succession and finds himself involved in a mysterious conspiracy, as two allies, siblings Eck and Sis Randolph tell them about the quest of gangster "Ape" Abrussi to get a hold of a super-weapons in order to turn his criminal empire into a literal one. Most of the book reads more like an espionage or thriller book than a science-fiction novel, with our scrappy heroes on the run from, captured by, escaped from, and recaptured by Abrussi, who turns out to have electroshock bracelets and an anechoic chamber designed for torture. We also find out that the the owners of Abrussi's captured weapons are aliens from Mercury and that they really want their technology back. At the end of the story, Abrussi is defeated, and it is revealed (in a seemingly semi-related point) that humans are being exposed to higher technology because we are soon going to have an intellectual revolution.
There are a few things that are awkward with this book. One of those is that the sequences of chases and captures seems more about padding out the length of the book than adding anything to the plot. Some of it seems like clear plot holes, with Abrussi recapturing a large base that had previously been taken over by the US military, who apparently didn't leave a sentry around. Also, the timeline of the book seems to need some explaining, since it takes place 20 years after it was written, and some of the events seem unlikely to have happened in 20 years time.
Despite that, there were several things promising about this book. For one thing, unlike many Ace Doubles, it has a female character who is more than a love interest or mysterious guide. It also has an African-American character in a major role (he is introduced at first as a janitor, but turns out to be a spy). This might not seem like a ringing endorsement now, but the broadening of representation in science-fiction happened incrementally. Also, while the story seems to feature lots of elements of noir, it concludes with a very hopeful and optimistic message about human potential. This is a perhaps coincidental connection with the other novel in the volume, "The Ladder in the Sky", which also featured a story that begin with noir elements, but revealed later that it was about aliens leading humans to higher potentials.
And as a final note, while the book's idea that goat-eyed, goat-horned humanoid aliens could exist on Mercury seems scientifically ludicrous today, it wasn't until the year that this book was written, in 1962, that Mariner 2, the first interplanetary mission, established that Venus was inhospitable. The idea that our solar system could be full of aliens was still an idea science-fiction writers could entertain into the mid-1960s.