Bad news. The Apocalypse is coming. Soon. Luckily, Heaven and Hell have left the business with the Anti-Christ in the hands of Crowley and Aziraphale, demon and angel respectively. Now they have misplaced the Anti-Christ and pretty much decided they really like humanity a lot more than their either of their bosses.
In the first edition, the full title of this book was "The Nice & Accurate Prophecies of Agnes Nutter, Witch." "Nice," in this context, meaning precisely correct. Agnes saw it all coming, from her being burned alive as a witch to the air force base where Armageddon will begin ("Peas is our professiune."). Agnes, her descendant, Anathema, the Four Horseman - Horsepersons - and the Other Four Horseman (a different chapter of Hell's Angels); it all comes together with the serried ranks of angels and demons gathered overhead.
Yes, this is an hysterically funny book. A satire and a parody, it lampoons everything in sight. From Elvis sightings to televangelists to the destruction of all intelligent life ("nothing left but dust and fundamentalists."), little escapes the scathing wit of Gaiman and Pratchett.
Of course the demon, Crowley, drives a 1926 Bentley. Of course any tape left in its glove box for more than two weeks turns into something by Queen. Of course the flaming sword used by War is delivered to her by International Express.
And what happens to the telephone solicitor, Lisa Morrow? Come on now, you secretly thought all telephone solicitors deserved it, right?
In the tradition of Jonathan Swift and Mark Twain, the satire makes a point. That point may be unpalatable to the religiously inflexible, or to those whose sense of righteousness hampers their sense of humor. Critics of Swift and Twain would find much to criticize in Good Omens. But Pratchett and Gaiman demonstrate that we don't need Heaven or Hell to have Good and Evil in the world; we have all we need in ourselves. It's the humanity of Adam Young, the Adversary, the Angel of the Bottomless Pit, etc., it's his human-ness that ultimately makes all the difference.
Don't read this book in bed; you'll keep your spouse awake, laughing out loud. But there's nothing else bad that can be said about it. Ineffability may be beyond our understanding, but humor, even humor in the face of the End of the World, we can understand.
Try this book. I will predict, with Agnes, you'll like it.