De revolutionibus orbium coelestium
Conversations on the Plurality of Worlds () is a popular science book by French author Bernard le Bovier de Fontenelle, published in 1686. It offered an explanation of the heliocentric model of the Universe, suggested by Nicolaus Copernicus in his 1543 work "De revolutionibus orbium coelestium". The book is Fontenelle's most famous work and is considered to be one of the first major works of the Age of Enlightenment.