A Reasonable World

Author, editor and critic Knight ( The Observers ) returns for a third time to the floating 21st-century prototype city Sea Venture, or CV. The alien intelligence discovered by Wallace McNulty in the first volume, a species which invades the minds of humans and animals, and (in the second volume) spread like an infection through CV and the rest of the world, has now reproduced in sufficient numbers to do more than observe its hosts. Disliking violence, the ``symbionts'' kill anyone who has the intention of harming another. Chaos spreads in the world, and researchers aboard CV are trying to find ways to destroy the parasites before they take complete control. Meanwhile, Knight uses characters from the first two volumes to explore rather bluntly a number interesting social and political issues, from the uselessness of a monetary economy to vegetarianism and animal experimentation. The characters often are just mouthpieces, carrying along the action and the moral debates but never fully emerging as genuine people. The prose is plain and clear, but the story jumps about wildly from one subplot to another, and Knight leaves many ends hanging, wrapping the tale up with a sweeping summary at the end. This might have been an engrossing entertainment with a strong base of thought-provoking issues, but the finish is a disappointment. (Mar.)