Foundation and Earth, by Isaac Asimov. New York: Doubleday and Co. 360 pp. $16.95. For the many Asimov fans, ``Foundation and Earth'' will be a long awaited capstone of the Foundation series. For those who have not yet discovered the marvelous imagination of Dr. Asimov, the book will be enjoyed on its own level as the adventures of Golan Trevize, a councilman of the Foundation who has decided that the plan to which the Foundation has been dedicated for the previous 500 years will not be followed. He alone had made the fateful decision of how the galaxy would develop and watched as his decision was put into action. Even as the story opens he wonders:
```Why did I do it?' asked Golan Trevize.... Why did I do it? Why did I do it?'''
From this beginning Trevize leads a wide-ranging expedition across the galaxy in search of Earth and an answer. We visit Comporellen, Aurora, Solaria, Melpomenia, Alpha, and finally Earth. On each there are special dangers for Trevize and his companions. Pelorat -- an old scholar whose specialty is the ancient legends of Earth, and Bliss -- Pelorat's young wife. Each planet visited brings them closer to their final destination -- Earth, the cradle of their humanity, the source of all the rest. Each planet has its own story to tell, a different path the ancient colonizers from Earth took. Some are overtly hostile, others seem harmless, but hold within themselves life-threatening challenges for the visitors.
One good example of Asimov's ingenuity is Solaria, a world in which only a few Solarians exist, each with a large estate. Robots do the work, the building, the raising of a single heir to the estate, and by and large provide the only companion the owner of the estate has. Of course occasionally an estate owner will consult with other estate holders but generally they regard that as unenjoyable. Solarians are hermaphrodites, and in addition have two small egg-shaped lobes at the base of their brains -- transducers. These allow the Solarians to use the heat flow from his portion of the world's surface to power his robots, heat his home, light his rooms, and protect his estate. What help can a Solarian be to Trevize in his search?
``Foundation and Earth'' brings together a number of Asimov's favorite themes. The longtime Asimov fan will find himself rereading many of Asimov's other science fiction novels -- not just those in the Foundation series. Those for whom this is the first taste of Asimov's writing will find a whole galaxy of other novels waiting.