Arthur C. Clarke: The Space Odyssey Series

This is a series of science fiction stories and novels that take place over a fairly long period of time and in different parts of the universe. In general, the main characters and settings differ in each of the works.
Bold type indicates a book I've read.

"The Sentinel" (written in 1948, first published in 1951 as "Sentinel of Eternity")
"Encounter at Dawn" (first published in 1953)
2001: A Space Odyssey (1968)
2010: Odyssey Two (1982)
2061: Odyssey Three (1987)
3001: The Final Odyssey (1997)

Frank Herbert: The Dune Saga

Main Characters: Duke Leto Atreides, head of House Atreides; Lady Jessica, concubine of the Duke, mother of Paul and Alia; Paul Atreides, the Duke's only surviving son; Alia Atreides, Paul's younger sister; many, many others
Setting: Mainly the planet Arrakis
Bold type indicates a book I've read.

Dune (1965)
Dune Messiah (1970)
Children of Dune (1976)
God Emperor of Dune (1981)
Heretics of Dune (1984)
Chapterhouse: Dune (1985)