Isaac Asimov's Robot series / R. Daneel Olivaw novel:
1. The Caves of Steel (1954)
2. The Naked Sun (1957)
3. The Robots of Dawn (1983)
4. Robots and Empire (1985)
IIRC 1st and 4th were the best, but would need to reread them all to be able to justify nowadays why.
Philip K. Dick's:
- The Three Stigmata of Palmer Eldritch (1964)
- Ubik (1969)
- A Scanner Darkly (1977)
I liked Ubik the most years ago, but not sure if today my rating would be the same.