Suggest me a book that low key radicalized you?

I’m looking for NONFICTION books that very subtly and unexpectedly challenged your worldview.

For example, I did not expect Killers of the Flower Moon to change my view on three-letter government agencies. Unbroken challenged my view of alcoholics.

In a similar vein, I watched The Whale recently and that made me come face-to-face with my fatphobia.

EDIT: this prompt was brought to you courtesy of my FIL who only reads nonfiction by male authors. I gifted him Killers of the Flower Moon because it appears as a murder mystery/FBI history. I don’t gift books I haven’t read, so need to find new options and most of my recent NF reads are not so subtle.

EDIT 2: NONFICTION PPL NONFICTION!!!!!!