The Sentinel, the short story that 2001 was based on was one of the first proper science fiction stories I read, and Arthur C. Clarke was one of the best creators of believable science fiction worlds. I always loved his three laws, especially the third one:
1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
3. Any sufficiently advanced technology is indistinguishable from magic.
I also love: "The truth, as always, will be far stranger."
Although for laugh out loud hialarity you can't beat his diary while working with Kubrick:
May 31. One hilarious idea we won't use. Seventeen alien, featureless black pyramids riding in open cars down Fifth Avenue, surrounded by Irish cops.
July 9. Spent much of afternoon teaching Stanley how to use the slide rule -- he's fascinated.
July 11. Joined Stanley to discuss plot development, but spent almost all the time arguing about Cantor's Theory of Transfinite Groups. Stanley tries to refute the "part equals the whole" paradox by arguing that a perfect square is not necessarily identical with the integer of the same value. I decide that he is a latent mathematical genius.
July 12. Now have everything -- except the plot.
October 17. Stanley has invented the wild idea of slightly fag robots who create a Victonan environment to put our heroes at their ease.
December l0. Stanley calls after screening H. G. Wells' Things to Come, and says he'll never see another movie I recommend.