How objective are books like “Sapiens: A Brief History of Humankind”? How are they “proven”?

Is Sapiens A philosophy book?

The book, focusing on Homo sapiens, surveys the history of humankind, starting from the Stone Age and going up to the twenty-first century.
Sapiens: A Brief History of Humankind.

First edition (English Version)
Author Yuval Noah Harari
Language Hebrew (2011), English (2015)
Subject History, social philosophy
Genre Nonfiction