Huxley, Thomas Henry
"Zeugnisse für die Stellung des Menschen in der Natur" by Thomas Henry Huxley is a book published in 1863. It presents the first comprehensive evidence for human evolution, arguing that humans and apes share a common ancestor. Through detailed anatomical comparisons, Huxley demonstrates that structural differences separating humans from gorillas are smaller than those separating gorillas from lower apes. The book boldly applies Darwin's evolutionary theory to humanity itself, challenging the idea that humans occupy a separate biological order from other primates. (This is an automatically generated summary.)
These books are free to read. Each is in the public domain in the United States; check your own country's rules before you copy or share one.