In the grand conclusion to the high-tech Threshold trilogy, test pilot Joe South returns from a prolonged visit with The Unity--a wiser, older coalition of lifeforms. But the benevolent aliens have a perplexing request that will pit human politicalMoreIn the grand conclusion to the high-tech Threshold trilogy, test pilot Joe South returns from a prolonged visit with The Unity--a wiser, older coalition of lifeforms. But the benevolent aliens have a perplexing request that will pit human political factions against each other.