"Ringworld" by Larry Niven (1970)
Larry Niven's most famous book is "Ringworld," so I suppose it's the best point of entry into his bibliography. It's also the only book of his that I've read, so I'm not prepared to say where this book stands in relation to his other novels. I've heard of "Ringworld" for years, but I only sat down and read it last month.
In "Ringworld," two humans and two aliens journey across the galaxy to a ring-shaped planet. One of the aliens is a member of a very advanced, technologically superior race fleeing some kind of Extinction Level Event at the center of the galaxy, while the other alien and the two humans join the expedition in order to receive a new kind of propulsion system. None of these characters know who (or what) created the Ringworld, how old it is, or why it was created.
What follows after the introductory chapters is a fairly by-the-numbers adventure story, not unlike something Jules Verne would have written. There is, however, a bit more "science" in this book, and I can understand why some people find it boring or "dry." Given our present understanding of the cosmos, the explosion at the center of the galaxy idea doesn't make a lot of sense, nor does the idea of a ring-shaped planet. Since planetary orbits involve both attraction and repulsion, a ring-shaped planet would tend to drift toward the star it is orbiting. Niven corrected this flaw in "Ringworld"'s sequel, "The Ringworld Engineers," but the explosion at the center of the galaxy remains an enigma.
All in all I thought it was a pretty good book, even though I have little desire to read its many sequels. Niven's characters are little more than cardboard cutouts, and I have the feeling that this series of novels would make even less sense as one proceeded through the later books. For sure, it's better than a lot of the crap out there, but not by much.