Are there non fiction books which are authentic and written in good faith?

I started reading Sapiens by Harari and ran into an article sometime later stating that it is full of errors and speculations. I enjoyed reading The Elegant Universe by Brian Greene but found out later that String Theory is kind of untestable and purely mathematical in nature. I am getting tired of picking non ficiton books which are inauthentic ramblings of people's opinion.

I want something authentic and written in good faith. What are your favorite non fiction books keeping this in mind?