Many science fiction readers are also fans of mysteries, perhaps because the two genres share an appeal to rational problem-solving. But combining the two genres in the same story is considered a difficult feat. David Brin's first novel, Sundiver, which launched his Uplift series, attempted this combination of genres. Now his latest novel returns to it.

Science fiction classically works by coming up with a single new idea, usually suggested by scientific speculation, and then exploring is consequences as logically as possible. Brin's idea in Kiln People is a new technology that makes it possible to duplicate people, not by cloning, but by infusing their spirits into clay doubles, or "dittos." This imaginary technology provides a way for Brin to explore issues of personal identity, agency, and responsibility, raised by more realistically plausible technologies from cloning to artificial intelligence. And lurking in the background is serious quantum mechanical speculation about the nature of consciousness.

In an ideal science fiction mystery, the crime that is being investigated ought to be one of the consequences of the scientific novelty, through which the author can explore it more fully. Brin makes good strategic use of his idea. The murder victim is one of the key researchers in the field. His old friend and his daughter are both involved in it as well. A secondary plot involves a criminal boss whose main racket is the illicit duplication of celebrity personalities. And the detective hero, Albert Morris, makes regular use of dittoing in his work. The novel's viewpoint characters include several of Albert's copies, going out to lead their brief lives running his errands. By asking questions about a murder, Morris raises questions about society and metaphysics that illuminate the novel's theme.

Is Brin's view of society a libertarian one? The social system Brin envisions seems not to be radically libertarian, but to have moved in a libertarian direction; several passages refer to a Great Deregulation, and most of what are currently prosecuted as crimes have become civil offenses, settled by payment of damages, un approach to crime many libertarians favor. Brin is at least giving his readers a low-key exposure to libertarian views. This kind of treatment seems consistent with his own view of himself as a libertarian.

The social implications of dittoing are somewhat ambiguous. On one hand, dittos look like a new category of slaves, beings capable of reason and choice that are someone else's property. And in fact Brin shows us a movement that calls for granting equal rights to dittos. But the practicality of such rights seems limited by the short ditto lifespan, only a day. And the need for it is reduced by the possibility of a ditto's memories being uploaded nto the orignal's brain at the end of its day. From one point of view, dittos represent a part of the original human being, temporarily detached and sent out to perform useful tasks. As such, they represent a science-fictional mechanism for diminishing the ultimate form of scarcity in human life—scarcity of time—by letting one person lead several lives in parallel.

And the core idea on which this is based is an affirmation of individual uniqueness, as an irreducible physical reality all the way down to the quantum level. Brin tells us that every self-aware being is absolutely distinct from every other and cannot be otherwise. Whatever the validity of the physics behind this—derived from recent speculations about the neural hasis of consciousness—it's certainly congenial to the individualism on which libertarian political thought is founded. So libertarians will certainly find Brin's ideas interesting. Add in a well-told noir detective story and this book is well worth reading.