Series
There are 7 books in the Foundation series.
Young mathematician Hari Seldon arrives on the imperial capital world with a theory that can predict the future, making him a target for political forces he barely understands. This prequel explores how psychohistory was born and how Seldon evolved from naive academic to revolutionary founder. Asimo
The 5 books listed here total 1,698 pages.
The Books Oracle — track the series you are partway through, and see what to read next.