In the Commentariolus (Little Commentary), Nicolaus Copernicus outlined his revolutionary Copernican heliocentrism theory of the solar system, about three decades before he finally published his major six volume work De revolutionibus orbium coelestium in 1543. Copernicus didn't publish the Commentariolus, and handed it only to few friends. It's unknown who received the Commentariolus, and when. He'd written the preliminary manuscript description of his early version of the theory sometime befor… (More on Commentariolus)