Perhaps as ubiquitous as smartphones today, the books of hours were a private necessity in Europe during the Middle Ages. These manuscripts contained collections of texts that were meaningful to each owner, as well as an organized method of structuring the day around prayer by marking the passing of the canonical hours. Although highly personalized, with intricate miniatures and illuminations, all books of hours contained sections to be recited at regular intervals throughout the twenty-four hours of the day. In them, the public and the private timescales converged, crystallized into a material, perdurable form not devoid of beauty. "The Book of Hours" by Frida Escobedo is a modern exegesis of this extinct devotional practice: a project in which twenty-four objects were photographed at different intervals of time to capture their evolution, making a new calendar of matter and light. As humanity has transitioned to a secular understanding of time in which hours are organized and conceived in terms of productivity, "The Book of Hours" interrogates the place of contemplation in our era, its possibility and necessity. Through this book - a public display of a private collection of objects - readers are invited to contemplate these arrays of matter and experience the ways in which they once interacted with light, that burning needle in time's template. / Wie verwandelt Licht die Objekte, auf die es scheint? Welche Auswirkungen haben solche Metamorphosen auf das architektonische Denken? Book of Hours versucht, diese Fragen zu beantworten. Zu diesem Zweck stellt es die Forschung der Architektin Frida Escobedo über die transformative Wirkung von Licht auf Materie vor. Zeitraffer zeigen den Prozess in Aktion, transluzentes Papier ahmt die durchlässige Barriere zwischen Lichtquellen und Objekten nach und inszeniert die Veränderlichkeit der Materie.