At that age, I was just getting into SF and loved everything by Asimov.
Still, I'll suggest starting with the following
The "I Robot" Short Story Collection
The Original Foundation trilogy:
1) Foundation
2) Foundation and Empire.
3) Second Foundation.
The Robots Series
1) The Caves of Steel
2) The Naked Sun
3) The Robots of Dawn
4) Robots and Empire
The Rest of His works can follow, depending on how he enjoys this.
I'll also recommend Most of Robert Heinleins work, though I enjoyed the following the most
1) Have Space Suit—Will Travel
2) The Moon is a Harsh Mistress
3) Glory Road
4) Time enough for Love
5) The Rolling Stones
6) Citizen of the Galaxy
7) Double Star
8) Methuselah's Children
I'll also suggest the works of E.E "Doc"Smith More specificly his Lensman series if you can find them as they are unfortunately no longer widely available. His is the first or one of the first space operas, and while dated is a lot of fun.
1) Triplanatery
2) First Lensman
3) Galactic Patrol
4) Grey Lensman
5) Second Stage Lensmen
6) Children of the Lens
In fantasy I'll suggest starting with the works of David Eddings.
Namely,
1) The Redemption of Althalus
2) The Belgariad series
- Pawn of Prophecy (1982)
- Queen of Sorcery (1982)
- Magician's Gambit (1983)
- Castle of Wizardry (1984)
- Enchanters' End Game (1984)
3) The Elenium series
- The Diamond Throne (1989)
- The Ruby Knight (1990)
- The Sapphire Rose (1991)
While I enjoy the sequels to the series as well. many only prefer the original series so I suggest he start with these.
Finally, anything and everything by Terry Pratchett. While many prefer to read in Publication order, I prefer to read in the individual series set in the same world. The L-Space website has a very handy reading guide which I have linked to below.
