Foundation and Earth<i> by Isaac Asimov (Doubleday: $16.95; 356 pp.)</i>

Isaac Asimov is arguably the most successful science fiction writer of all time. Of science fiction’s senior statesmen (Asimov, Arthur C. Clarke and Robert A. Heinlein), Asimov at 66 is the youngest and remains the most prolific of the three. His last two science-fiction novels, “The Foundation’s Edge” and “Robots of Dawn,” both enjoyed extended stays on The New York Times best-seller list and large advances for paperback rights. The novel reviewed here, “Foundation and Earth,” seems destined for the same fate.

This novel may (or may not) be the conclusion of the famous Foundation Series, the sweeping account of the fall and rise of galactic empires that now includes five volumes and has received a unique Hugo award as the best all-time science-fiction series. We follow the protagonists of “The Foundation’s Edge,” Councilman Golan Trevise of the First Foundation, the historian Janov Pelorat and his beautiful female companion, Bliss, who is a “component” of the planet-scale superorganism Gaia, as they search for a fabled lost planet called Earth, which legend holds is original home of mankind. Trevise’s search is complicated by the discovery that all historical mentions of Earth, its location and its history have been mysteriously deleted from the libraries of the Foundation and from other sources.

The hallmark of Asimov’s fiction has always been the intricate logical structure of his plots, the convoluted twists, the flawless logic, the tricky false resolutions, the surprising yet inevitable conclusions. His novels can usually be characterized as very rational mystery/detective stories transposed to a science-fiction setting. “Foundation and Earth” is no exception to this pattern. Here the twin mysteries are the location of Earth and the reason its location has been so carefully concealed. Trevise and his companions travel to seven planets in their quest, observing, discussing, arguing and theorizing as they go. And ultimately, they find the unexpected resolution of the mysteries.

As the novel proceeds, the plot elements and future histories of Asimov’s Foundation series and his Robot series are skillfully knitted together, uniting Asimov’s two major series into a seamless whole that encompasses both major works. Trevise and his companions travel to the abandoned planet Aurora (locale of “Robots of Dawn”) and later encounter the static human/robot society of isolated Solaria (locale of “The Naked Sun”) in search of clues to the Earth’s location, providing us in the process with clues to the fate of these robot-based Space colonies described in Asimov’s earlier works.

But despite tie-ins and retrospective references, “Foundation and Earth” is a coherent whole which stands on its own. If it lacks the youthful enthusiasm and inventiveness of the seminal novel “Foundation,” written in 1941 when Asimov was 21 years old, it has the solid workmanship and skill of the mature master. And in some ways, Asimov at 66 is still improving. His deft handling of sexual themes and female characters are relatively new aspects of his writing. I liked this novel better than “Foundation’s Edge,” winner of the 1982 Hugo award. It is well-done and upholds the overall quality standard of the Foundation series. The success it will certainly achieve is well-deserved.

Does the Foundation series really end here? Near the end of the novel, we are given a clue to what may be yet to come. An idiosyncrasy of Asimov’s Foundation/Robot universe has always been that mankind has expanded into an empty and almost lifeless galaxy with no intelligent aliens, a galaxy where men and the robots are the only intelligent life forms. Now we receive a hint that there may be intelligent alien life in other galaxies and that mankind and these aliens may be destined to meet. Isaac Asimov is an amazingly prolific writer, and he has been well rewarded for his recent efforts. I would not want to bet that “Foundation and Earth” is really the conclusion of the Foundation series.