Expedition to Earth

I think Clarke is at his best in his shorter works, and this is one of his best collections, with several good stories, including "Second Dawn," "History Lesson," and "The Sentinel" (one of the stories which 2001 was based on). Clarke is often thought of as a Hard SF writer, but also has his poetic, even mystical, side. As (I think) Brian Aldiss put it, his work partakes of both the thinking and dreaming poles of science fiction.