When Bernard de Fontenelle published the first edition of his Entretiens sur la Pluralite des Mondes in 1686, it was an immediate success. In an age when women, even those from the richest and most distinguished families, received little or no formal education, it offered an entertaining and accessible introduction to astronomy and some of the burning topics of the day. Does the earth really go around the sun? Are there other inhabited planets out there? If so, are the inhabitants like us or quite different? Is the moon itself inhabited? Is even the sun inhabited? Are there volcanoes on the...