"Unnatural" by Philip Ball. It's a book about the history of "anthropoeia" which is his term for the "technology to make people". It's very interesting. He explores the old "making people" myths of the alchemists, then he moves onto the early fiction novels like Faust and Frankenstein, before talking about the recent advances in cloning technology, all the while he also explains society's reaction to the myths and the technologies.
It's an even handed account that does not demonize science or dismiss some of the valid concerns people have about any technology that could be used to grow/modify people artificially. Honestly, it's a very good book, which explains the issues very clearly. It's entertaining to read and it's not all that long either.
Another very interesting non-fiction book is "Rubicon" by Tom Holland. It details how the Roman Republic fell apart and how Caesar ascended to power. Trust me, it's very interesting. Murder, war, mayhem, corruption, political skull-duggery and assassinations play a prominent role. Tom Holland does not write boring books - he takes the time to make history interesting.
If you really dislike non-fiction, then you could try Catch-22. Can't go wrong with Catch-22. And if you liked Hitchhiker's Guide, then you would probably enjoy "Dirk Gently's Holistic Detective Agency", also written by Douglas Adams. It's not as good or as funny as Hitchhiker's guide, but it's still good. I really did not care for "Dark tea-time of the soul", though.
And I have to recommend "Hello America" and "Millennium People" by J.G Ballard. Not enough people read J.G Ballard. "Hello America" deals with an exploration team sent to the US, which has been devastated and abandoned almost entirely due to a environmental catastrophe engineered by the USSR (it was written when the USSR was still around). It's really interesting and it really captures the spirit of America, because it makes you think about how much the world would lose if it lost the USA entirely. "Millennium People" is about anarchy and middle-class "soft" terrorists and their violent response to their "boring" lives in modern day UK society - it's essentially about people setting off bombs merely for excitement and it explores the psychology of what happens when people snap.
Another very interesting book is "Cloud Atlas" by English Author David Mitchell (not the comedian). It's a very surreal book and very well written.