Nothing to do with stigmata, really, and the titular differences aren't even mentioned until three-quarters of the way through the book. It's almost as if Dick wanted to use the title, and then realised, "Oh, I haven't said what these stigmata are yet, or why. Better throw them in." Because they are also entirely irrelevant to the story.
Oh yes, the story. Hmm. It’s not one of Dick’s best, and a lot of it barely makes sense. Or at least, it makes sense in that it’s internally consistent. But it’s hard to believe. The UN conscripts people using a military-style draft, to go and live on the colonies – Mars is the only one we see, but several other planets and moons within the solar system are implied.
Colonists' lives are so hard and unpleasant that the only way they can get by – and the only entertainment they have, it seems – is to lose themselves in shared hallucinations induced by a drug called Can-D, during which they enter the world of characters called Perky Pat and her boyfriend Walt. These are inspired or induced using “layouts” – groupings of miniaturised artefacts that become part of Pat’s life, and hence of the colonists' hallucinations.
In any group entering the shared experience, all the women always take the part of Pat, and all the men that of Walt. Which seems very limiting and heteronormative.
And, oh, yes, the sexual politics.
In some ways they’re not too bad. The main character, Barney Mayerson, is a precog – oh yes, we have those, too, except when we forget that we do – and his assistant, Roni Fugate, ends up with his job, which is a quite a senior one at the company that makes “mins” – miniaturised items for use with the Perky Pat layouts. They use their precognitive powers to know what items are going to be fashionable. Other than that, the existence of reliable precognition seems to have had no impact on society.
Maybe that’s why he wrote “Minority Report.”
Anyway, at the start, she is also his lover, which seems to have happened as soon as she started working with him, almost as a given.
On the other hand, a significant part of the plot is driven by the fact that he has never got over his breakup with his wife – which I think might have been as long as twenty years ago – whom he dumped because she was bad for his career, or something.
In fact she’s a highly skilled potter, who makes artefacts that are miniaturised for use in these famous layouts. Mayerson rejects her latest designs, saying they won’t be successful, when Roni says they will. His attempt to screw up his ex’s career leads her (and her new husband, who is acting as her salesman) into the arms of a rival corporation.
That body has been set up by the mysterious titular character. Palmer Eldritch has just returned from a ten-year trip to the Proxima system, whence he might have bought back a new drug, Chew-Z, that has similar properties to Can-D but is even more powerful.
Also global warming: the world is unliveably hot, so everyone stays in air-conditioned buildings (and makes things worse). In America, at least. We don’t hear anything about the rest of the world. And forced “evolution”: some people go for expensive treatments in Swiss clinics, which give them bigger brains and leathery skin, at least on their head. Though sometimes it goes wrong and their intelligence decreases.
It’s all quite, quite mad, and the conclusion probably makes even less sense. But what the hell, it’s fun enough while it lasts.