"What kind of books do you like reading?"
While this sentence seems straightforward enough, I have a problem seeing how the "kind of" is expressed here. To me it seems to mean "what books do you like to read?" minus the specifing "kind of". There is another sentence eleswhere in this chapter which also has the "kind of" issue, but it is structured differently: 她最喜欢听什么音乐？"What kind of music does she like listening to most?". This to me also seems to mean simply "What music does she like the most?"
Perhaps I am overthinking this, but I would love to get an expert opinion :)
When I lived in China, people used 哪种 to ask "what kind?" I'm not sure that applies to this question, though, because when asking a person what kind of books they like to read, the implied question is "which genre?" which would be another word altogether in Chinese.
Either way, Duo's English translation of 你喜欢看什么书 does not seem correct.
I'm not an expert, but I think a more appropriate translation would be: 你喜欢看什么样的书？