Convoluted and Unconvincing
Even by PKD's standards, this is a convoluted novel. Dick himself wrote in reference to it, "I not only cannot understand the novel, I can't even read it." Understandable, considering that the story revolves around drugs that project the user's consciousness into illusory "realities," and the characters aren't always sure whether they're currently stoned. It starts out straightforward enough - promising, even - but eventually takes a downturn into psychedelia from which it never recovers.
Convolution aside, Dick does a much poorer job than usual here of making his "science" credible. That there are drugs that produce fully realized and realistic illusions I can accept readily enough, but that toking them is a group experience and that they require physical dollhouse props into which they somehow project the user's consciousness is stretching things a bit far. That alone I could handle, but there's also the matter of what Dick calls "E-Therapy," which is described as being a treatment that accelerates the process of evolution. Dick's idea of evolution, however, is not the genuine scientific theory, but the sort of half-formed notion that one might expect a very young child to get out of an explanation of the term: evolution, according to Dick, is a linear, predictable process that progresses not as mutations occur in the reproductive cycle, but as mutations occur in individual organisms over their lifetimes. Even the explanations of precognition aren't as believable as they are in Dick's other precog stories.