1_Star Maker by Olaf Stapledon
When I read this book I was totally blown away. The sheer scale of it, the ideas and concepts explored. It is litterally a history of the universe from beginning to end - with some of the most imaginative alien cultures and civilizations I've ever come across. Whats more is when you find out what the "Star Makers" themselves actually are. Mind blowing. The Arthur C Clarke quote on the front cover is certainly there for a reason.
2_Dragon's Egg by Robert L Forward
The story of an alien civilization that has managed to evolve on a dying neutron star. We watch the Cheelah from the beginning as simple tribes and then watch them evolve into a more high-tech society, we see them make costly mistakes and evolve. Brilliant stuff that really excited my imagination as a kid. Nowadays I can appreciate it in a different light as Forward was a scientist and so the science is very hard and accurate - and this only adds to making it more believable in my eyes.
3_Mission of Gravity by Hal Clement
Yet another hard sci-fi classic, this time that takes place on an Oblate planet, which is why it has varied gravity all over it. A pretty fascinating concept and makes you wonder if such a world might exist out there. A great story, and another that puts a non-humanoid alien as one of the central protagonists - this time a rather likeable alien centipede-like creature. Like Dragon's Egg - the science is very accurate and realistic which for me just makes it that bit more enjoyable to read.
4_2001 A Space Odyessy by Arthur C Clarke
Does this one really need any introductions? One of the best hard sci-fi novels of all time, and very likely to be the most known and famous. I guess with this one, Clarke managed to put Hard sci-fi into the mainstream for a while, what with the film and all that. An impressive feat and accomplishment and one I wish I had the talent myself, so I have often looked up to Clarke and would love to be as good as he was.
5_The Shadow out Of Time by HP Lovecraft
While I loved At the mountains of madness, this one blew me away even more and eventually became my all time favourite Cosmic Horror story. The histories and alien races described are mind-blowing and exciting - with the amazing Great Race of Yith and their mortal enemies the Flying Polyps - both of which became two of my all time favourite sci-fi alien races. The story is a perfect mix of that hard boiled detective style film noir and mind melting cosmic horror to make you feel very very insignificant in the universe.
