"The Eden Cycle" by Ramond Z. Gallun (1974)
I'd like to think I've read a few books that were ahead of their time. "Moby Dick," for example, or "VALIS." Maybe even "American Psycho" or "A Canticle for Leibowitz." But this book, "The Eden Cycle," might be so far ahead of its time that it has yet to find an audience. It might be that Mr. Gallun was writing not for the present future that we represent, but for a future still further removed from his own time, and ours.
At some point in the future (or is it at some point in the past?), an alien race sends us the blueprints for the ultimate virtual reality machine. Once connected to this machine, the user experiences a godlike existence, wherein death, illness, and isolation become things of the past - unless the user wills it otherwise. The user is free to construct a world in which he or she possesses superhuman powers, in which myths are made real, or any number of other possibilities - all under the guidance of the machine's designers, who are never seen, but who are heard from often.
Within one of the worlds created by this machine we find a two characters, perhaps best referred to as "male" and "female." Their love for one another remains one of the only constants in the book, and their quest to uncover the true nature of "reality" forms the bulk of the narrative.
As they pass through virtual world after virtual world, they are beset by questions. What is real? How long have we been here? What is the value of reality? Is human existence made better through adversity? Many of these questions remain unanswered at the conclusion of the book, and the author provides no easy answers for these facets of human existence. Even the ending is ambiguous. Did they really leave the machine? Or were they merely experiencing another virtual world? It is rare to encounter science fiction novels of such existential depth, and I doubt I'll be encountering another such book any time soon.
And of course, the plot devices described above will bring "The Matrix" films to mind, or even the lesser-known "Dark City." But where the two movies offer action with a side of existentialism, "The Eden Cycle" offers a compelling, heartfelt story, centered around the crucial questions of human existence. Sure, I liked the movies, but "The Eden Cycle" is so much weightier than either. It is, moreover, a much earlier effort, having appeared long before the films.
I would encourage you to read this book. The paperback version can be a bit difficult to track down, but it's worth locating. It's slower going than the more generic type of science fiction, but you won't be sorry you took the time to read it.