The "Commentariolus" ("Little Commentary") is Nicolaus Copernicus's forty-page outline of an early version of his revolutionary heliocentric theory of the universe. After further long development of his theory, Copernicus published the mature version in 1543 in his landmark work, De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres). Copernicus wrote the "Commentariolus" some time before 1514 and circulated copies to his friends and colleagues. It thus became known amo… (More on Commentariolus)