Isaac Asimov is considered the most prolific science fiction author. He wrote
well over a hundred books. His Foundation Series is considered the most popular
science fiction series ever. My opinion is that the first three books listed
above are entertaining and thought provoking. They are put together as a series
of short stories (chapters) covering critical events over time, like snapshots
of history. This was lent to their first printing as serials in speculative
fiction magazines during the 1950's.
After a number of years, Asimov returned to the Foundation Series with several
more novels: Foundation's
Edge, Foundation and Earth, Prelude
to Foundation and Forward
the Foundation. Of these I have read three. The fourth is strangely
out of print (and thus no link). I found Forward
the Foundation entertaining, but it seemed to bear little resemblance
to the rest of the series. The other two books had wonderful potential, but
neither seemed to carry through on their beginnings.
His best work in my opinion would easily be the compilation of short stories
that make up I,
Robot, which were also first printed as serials. Each story contains
a moral dilemma that is put in black and white by using robots rather than humans.
In these stories, he also came up with the "Three Laws of Robotics" (only later
adding the Zeroth Law). If you really enjoy I, Robot then The
Caves of Steel and The
Naked Sun, which continue to follow the exploits of R. Daneel Olivaw.