On 31 December 1870, the Swiss philosopher, Henri-Frédéric Amiel (1821–1881), petitioned the municipal authorities of Geneva on behalf of his neighbours and himself. They lived in a street called the Rue des Belles Filles (“beautiful girls' street”) and wanted to have the name of their street changed because it alluded to prostitutes. This is just one among a multitude of historical facts that have come down to us because humble (or not so humble) suppliants put them on paper in the form of a petition, and the authorities to which these petitions were addressed took care to preserve them. Writing petitions was a common human experience. “Everybody is free to write petitions and have a drink of water”, as a traditional German saying would have it. However, as opposed to drinking water, writing petitions is an act which produces historical sources, many of which have survived. The aim of this volume is to give an overview of their importance as sources for social history.