I sometimes find myself thinking, "How did all this get started??" I wonder who was the first to do something, and how, exactly, we got from there to here. Because of this I lost an hour the other day looking up how RPGs and LARPs developed out of wargames and historical reinactment. (That doesn't relate to anything in this post.) Larry Niven's Ringworld was the first of a scifi genre that has come to be known as The Enormous Big Thing or the Big Dumb Thing. You know the plot: explorers come across a mind-blowingly huge and scientifically important discovery, and them spend the rest of the story trying to figure it out.
Niven's Ringworld is an object that masses the same as Jupiter, stretched out along a ribbon that matches Earths orbit around the sun. The exterior is an unknown material which protects the interior from the dangers of space. The interior is a sculpted landscape with three million times the surface area of Earth. It rotates at 770 miles/second, creating a centrifugal effect similar to that of Earth's gravity. Who built it? Why did they build it? What can we do with it? How can we exploit it to our purposes? These are the questions that the saga in built around, with good plotwork thrown in to create readable books.
Ringworld was published in 1970 as a stand-alone novel. It was well received, winning the Hugo, Nebula, and Locus awards. It describes the adventures of Louis Wu, a space explorer from Earth who is drafted by the Pierson's puppeteer to explore the newly-discovered Ringworld. Speaker-to-Animals, a diplomat from the fierce catlike Kzin race and Teela Brown, a human woman bred for luck make the rest of the expedition.
I'm under the impression that the other books weren't exactly planned when Niven released Ringworld. Ten years later, the second book, The Ringworld Engineers, came about largely because various readers pointed out problems with the science of the Ringworld. The object was unstable, and about to crash into its sun. Wu and Speaker (now called Chmeee) are brought again to the Ringworld, and more is learned about its creators and its inhabitants as the expedition endeavors to save the world from incineration. Book #3 The Ringworld Throne describes the struggle of to wrest control of the world and its peoples out of manipulative hands into more nurturing ones. It was released sixteen years after The Ringworld Engineers. A gap of eight years separates the final book, Ringworld's Children. Niven's voice is distinctly different in each of the books. The first one has a very hard scifi feel to it, with more time given to describing the setting and the objects than to character development. Dialogue is flat, and it ca be difficult to tell who is speaking. In books three and four, the plot is much more character driven and Niven gives voice to more characters, allowing the reader to see from different viewpoints. The fourth book was the easiest for me to read.
I rather enjoyed the series. It exists within Niven's futuristic Known Space universe. There are some points where, arguably, knowing more of the Known Space history would be useful to the reader. I came into it with almost no knowledge of the setting, and was able to grasp the ideas handily. I would recommend starting with Ringworld, because it really sets the stage; the other books spend less time on the description of the Ringworld. The rest of the books are better plotted, however, and more fun to read.