So, there’s a planet, and on the planet there’s a human settlement, or area of settlement, which humans don’t go far from, and there are also intelligent aliens. The humans and the aliens have been in contact for a while, but the humans don’t really understand the aliens. Then our protagonist is captured by the aliens, or goes to a part of the planet where humans don’t go, and discovers the fascinating truth about the aliens. This usually but not always leads to better a human/alien relationship thereafter.
How many books fit that template?
In my post on Octavia Butler’s Survivor, I suggested three other examples: Marion Zimmer Bradley’s Star of Danger (and I could have added Darkover Landfall), C.J. Cherryh’s Forty Thousand in Gehenna, and Judith Moffett’s Pennterra. In comments people mentioned Orson Scott Card’s Speaker for the Dead, Mary Doria Russell’s The Sparrow, Jonathan Lethem’s Girl in Landscape, Amy Thomson’s The Color of Distance, Ursula Le Guin’s Rocannon’s World, Planet of Exile and The Left Hand of Darkness (though that doesn’t have a human settlement) and I further thought of Mary Gentle’s Golden Witchbreed and Nicola Griffith’s Ammonite. Please suggest more in comments if you have some!
In that lot we have some variation on a theme. Some of the “aliens” are practically human and some of them are really really alien. Sometimes things turn out well, sometimes terribly. Sometimes the protagonist goes native, sometimes the aliens get destroyed. But with all those variations, we also definitely have a theme.