Keith Stoner and his family return to Earth at the end of their interstellar trip, which was started in Voyagers III. They return to a Solar System which is much changed.
Mr. Bova has spent the years since writing Voyagers III writing his "Grand Tour of the Solar System" series, in which he describes a future history of Earth at odds with itself - incredible technical advances on the one hand, coupled with religious fundamentalism (Muslim, Christian and you name it) on the other. In this book he attempts to merge the two series by using the "many worlds" theory of Quantum Mechanics to introduce Stoner et al. into the "Grand Tour" hustory. The attempt is not successful.
Very interesting book, it combines the two story lines of differnet books into one, heading towards maybe a third. The third I would say is the Orion Series because of similarities of the space-time contiuem being impeaded into different channels of the cosmic ocean. Thus i would say gives scope to advance the human species into a much greater being and the off spring Kieth Stoner might just become the masters of the universe. Rick seems to be a lot more head strong than Cathy and could in the future be able to transform himself into pure energy and start to rule the universe. Just a thought. But the book itself is very entetaining and gives rise to the event of humans coming into full contact with aliens after being able to fulfil it's own destiny in finding viable solutions of the planets problems.