Swiss art historian and herald of modern architecture Sigfried Giedion (1888–1968) had a new history in mind when he began working on an ambitious book project in 1929. The book was to span from around 1750 to his time of writing in the 1930s. Multivolume and multidisciplinary, it was intended to serve as a document for diagnosing the time period and for orientation within an age perceived as chaotic. For various reasons, the project was interrupted in 1938 and remained unfinished. The material left behind – a wealth of texts, images, and records – can be grouped around three overarching civilizational themes: industrialization, social welfare, and modern art. This heterogeneous bundle has been edited into a single collection that provides new, often unexpected insights into Giedion’s historical agenda beyond his well-known publications, plus a fascinating glimpse into his toolbox.