Who were the Zurich Pietists in the late 17th and early 18th centuries when the piety movement began to form? What social milieu did they come from? What was on their mind and what were they reading? What were their hopes and how did they relate to their social environment? Kaspar Bütikofer investigates these questions based on a wide range of sources. In addition to files from two Pietist trials, he evaluates in particular the library and the life testimonies of the Pietist merchant, Johann Heinrich Locher (1648-1718), which opens up the way of thinking and living in Zurich Pietism. Finally, he examines the involvement of the Pietist reform movement in the constitutional disturbances of 1713.