This publication is devoted to a little-known temporary artwork: in the winter of 1973/74 Paul Thek was a guest of the Lehmbruck-Museum in Duisburg. His expansive environment 'Ark, Pyramid - Christmas' ('The Manger') filled a whole room. It was the further development of his installation realized at the documenta 5 in Kassel (1972). This exhibition, organised by the director of the museum at the time, Siegfried Salzmann (1985-1993), was the fourth in Thek's series of atmospheric, large-scale projects in Europe, which engaged with individualised religious symbols. The festive period provided Thek with the occasion to present, for the first time, a self-written theatre piece in the form of a nativity play featuring children from Duisburg. A great quantity of original material and documents have been discovered in the museum's repository and enable a reconstruction of the exhibition in this book. Exhibition: Lehmbruck Museum Duisburg, Germany (27.04-28.07.2012).