How the discovery of the present has changed the world. A life without appointments is hardly imaginable today. Time is a precious commodity that needs to be managed and utilized. Yet, time is primarily an idea. The renowned historian Achim Landwehr compellingly and plausibly narrates how, in the 17th century, people's relationship with time—regarding the present, future, and past—changed. Until then, most people in Europe believed that the apocalypse and the kingdom of God were imminent—so why shape the present if it couldn't change the future? However, gradually both the present and the future began to be perceived as periods of possibilities. This was reflected in many small changes: calendars, which had previously consisted of densely printed pages with astrological information, now offered space for personal entries.