Just finished reading THE THREE SIGMATA OF PALMER ELDRITCH. Whew, what a crazy book! really enjoyed it.
Can I talk about it with some spoilers? If you don't want to read anything about it, plz skip. I'll only talk about the world itself, not the plot.
The book, set in the space travel far future of 2016, follows a few characters who work for these drug companies. The earth is now increasingly uninhabitable due to global warming, and so people are being "drafted" to live in colonies on other planets. Mars is a grim hellworld which is basically a labor camp, but they don't specify exactly why it's so hellish, just that people there are all suicidally depressed and need to do heavy hallucinogens in order to cope with it.
The first drug, Can-D, lets people escape into a communal transcendental experience. They chew up the drug together, and then they appear in this fantasy world which is Earth, New York, in the 1970s. (er.. present day) While tripping, you inhabit the bodies of these specific people - males become Walt and females become Pat. They call this experience Translation. If multiple people are translated at once, they share a body - so all the men are sharing Walt's body and collectively deciding how he'll behave. Furthermore, when you do the drug, you have to sit in these "layouts"... basically like a little doll house. You can buy "min" furniture (basically doll furniture), or other items, and it will appear in your trip. So if you buy this fancy wardrobe, then when you're "translated", it appears in your experience. So there's a materialistic component to it.
The rival drug, Chew-Z, lets people escape into a personal transcendental experience. You can imagine anything you want, and it seems real, but you're alone. You could live in a memory, or a fantasy. Essentially, you are in a mind. But whose mind? maybe it's not yours...
Both drugs are incredibly habit forming, and the colonists on mars are badly addicted. These experiences - which the users regard as spirituality, true religion - are the exact experiences permitted by the drug manufacturers. Users feel like their soul actually moves into another body, which proves (to many) that souls are real and the material world torturing us is actually an illusion. But any of these translation experiences are actually controlled by the company that prodces the drug.
PKD is commenting on two types of transcendental experiences... but rather than the experience itself, he's more interested in where they come from. Who offers them. People are transformed by religious experiences, and then become servants of whoever offered it. Trapped in a mode of thinking. Freed into a form of bondage.
There's a lot more going on in this book than that. Without spoiling the plot too much, I'll mention that this is another book where PKD explores religion with a very skeptical attitude. He views religious experiences as real, but does not take the church's explanation at face value. A lot of his books seem to say -- the bible actually is divinely inspired, but we shouldn't trust God's statement about who or what he is. We all bought into this ancient/medieval idea of god, but what if it's more like an alien invader? what if god is wrong about himself, and only thinks he's perfect? What if creation is flawed in ways that god cannot understand (in the same way that a psychotic person cannot perceive their own psychosis)?