Dialogue Concerning the Two Chief World Systems – Galileo Galilei by Galileo Galilei

"And yet it moves."

Galileo presents a debate between three characters over the merits of the ancient Ptolemaic system (Earth-centered) and the new Copernican system (Sun-centered). Writing in Italian rather than Latin to reach a broad audience, he uses wit and clear logic to dismantle the old physics and champion the motion of the Earth.

This book led to Galileo's trial by the Inquisition. It is a landmark in the history of science, not only for its defense of heliocentrism but for its method: using observation and reason to challenge authority. It marks the birth of modern scientific writing.