Space travel leading to skylife is vital to human survival, because the question is not whether we will be hit by an asteroid, but when. A planetary culture that does not develop spacefaring is courting suicide. All our history, all our social progress and growing insight will be for nothing if we perish. No risk of this kind, however small it might be argued to be, is worth taking, and no cost to prevent it is too great. No level of risk is acceptable when it comes to all or nothing survival.

In a tough situation, don't avoid acting just because it's easier or comfortable. Don't lapse into a passive state. People who give up, die.

Once you've grown up in space, moving on means moving out, not going back to Earth. Nobody wants to be a groundpounder.

If you are losing at a game, change the game.

SF is a controlled way to think and dream about the future. An integration of the mood and attitude of science (the objective universe) with the fears and hopes that spring from the unconscious. Anything that turns you and your social context, the social you, inside out. Nightmares and visions, always outlined by the barely possible.

Jeff Carver is a hard sf writer who gets it right-his science and his people are equally convincing. NEPTUNE CROSSING combines his strengths, from a chilling look at alien machine intelligence, to cutting-edge chaos theory, to the pangs of finite humans in the face of the infinite. If you like intriguing ideas delivered in an exciting plot, this is your meat.

Any technology that is distinguishable from magic is not sufficiently advanced.