Quarantine begins rather ordinarily as an investigation into the disappearance of a patient from a mental institute. From this simple beginning, Egan creates a thoroughly original piece of science fiction which explores the very nature of reality as dictated by quantum theory.

In the not too distant future, our solar system becomes enveloped by an impenetrable sphere known simply as the Bubble. Its origins are unknown as are its implications for our future. Widespread rioting and panic occurs soon after its appearance and a variety of cults emerge to explain its existence.

The future Egan envisions is one in which technology has permeated nearly every aspect of our daily lives. The novel has a definitive "cyberpunk" feel to it as many of the characters utilize neural mods to enhance their physical and intellectual capabalities. Nanotechnology has become the critical enabler of this technological revolution.

The novel centers around the protagonist, Nick Stavrianos, a private investigator hired by an anonymous client to solve the disappearance of the mental patient. Nick's investigation quickly leads him to a shadowy organization known as "the Ensemble", who are intimately linked with the patient's disappearance.

From this point, the reader is plunged into the esoteric world of quantum theory and here Egan shatters our perceptions of reality and builds a new order where the old rules no longer apply. I won't be giving too much of the plot away by saying that a majority of the novel has to do with the collapse of the wave function and its resulting consequences for the evolution of life in our universe.

I'd like to digress a bit and discuss quantum theory a bit, mainly because I'm fascinated by it. Egan seems to have chosen to champion the Copenhagen interpretation of quantum theory that was formulated by Neils Bohr. Bohr, unlike his contemporaries, sought to find a suitable interpretation of the newly developed theory and gain a greater understanding of the nature of reality.

The Copenhagen interpretation ultimately rejected determinism and the notion of an "objective" reality. The key distinction was that material reality depends in part on how we chose to view it. Of course, this is rather counter-intuitive and is what delayed the acceptance of quantum theory by a number of scientists. Einstein himself was one of the theory's most outspoken opponents.

In Quarantine, Egan examines the role of the "observer" in collapsing the wave function and the implications of a conscious observer who is able to influence their view of reality. The wave function describes all the possible states for a quantum system, which exist in a state of superposition in the abscence of an observer. However, once the system is observed, the states "collapse" into one specific configuration dictated by the probability distribution contained in its wave function.

Egan makes the conjecture that there is a disconnect between observing and actually collapsing the wave function. He also makes a large assumption in assuming these rules translate from the quantum level to the macroscopic level.

Quarantine makes for a highly challenging and thought-provoking read. Naturally, it won't appeal to everyone. It's a rather short novel, but I found myself having to re-read certain passages to make sure I was really understanding things and I consider myself to be fairly knowledgeable about quantum theory. While Egan makes his ideas accesible to the average reader, you would certainly benefit from having some rudimentary knowledge of quantum theory beforehand.

Egan's interpretations of quantum theory appear plausible and raise interesting questions about our perceptions of reality. He manages to steer clear of overly metaphysical explanations or resorting to some form of solipsism to explain away the more difficult questions. Interestingly, few scientists are interested in the actual interpretations of quantum theory. They merely view it as a mathematical framework for describing the subatomic world and would never consider it a descriptive theory of existence. I applaud Egan's attempt to address the tough questions that quantum theory brings up.

Incidentally, if you are interested in gaining a better understanding of quantum theory, I highly recommend The Cosmic Code by Heinz Pagels. It is the best-written book on the subject for laymen that I've ever come across and presents the material in a lucid manner without overwhelming the reader with mathematical minutae.