Dune

I still have the copy I bought, back there in 1974, and which I read in a single sitting one rainy weekend in Cape Town, in my residence room.

I have lent it to numerous people, and it has always come back - and everyone I ever lent it to, or recommended it to, has had much the same reaction: Simply Awesome.

This was so good on so many levels, it is hard to know where to start. Herbert created a large and complex universe, with a complicated history - and then pitchforks you into it, right in amidst the intrigues of the Great Houses in the Imperium, and the machinations of the Bene Gesserit. The necessity of the spice from Arrakis for the functioning of FTL travel was interesting; so too the dependence on sentient Navigators for negotiating the strange galactic byways - and the use of human computers (mentats) in the place of AI was weirdly Luddite, but understandable in terms of the anti-technological Butlerian Jihad. With the use of that term predating any al-Qaeda references, note!

I was captivated by this book. I liked the sequel, too, which came out shortly after I bought Dune. The third, not so much. The rest of them? Stop with Due Messiah: you'll be glad you did. And under NO circumstances read the reboot by his son; it's simply dreadful.