I'm not a fan of fiction books.

Fiction relies on made-up characters, plots, and metaphors to explore aspects of reality and human nature.

I find it much more fun to learn the core ideas presented directly.

Co-Founder at sablier.com, and open-source developer. I have a broad range of interests, including longevity, epistemology, physics, and psychology.

You reality might be much more fictional that you think it is

july

creating and destroying; built flying cars & autonomous vehicles, now building /faust, more here: /july, web: july.rocks

This is a play on the meanings of words.

Science and philosophy are both conjectural.

The 'made up' in the OP referred to the additional baggage that surrounds the core ideas.

So we have:

non-fiction → 'made-up' guesses about reality

fiction → 'made-up' guesses about reality with additional 'made-up' baggage

If you writing those definitions, you still didn't get it. 
Your reality might be much more fictional than you think.