Coinciding with museum exhibitions by Thomas Ruff in Ghent and Düsseldorf, this book comprises five series of photos ranging from the start of Ruffs' artistic career in the late 1970s to recent work in 2014. This selection, being shown under the title Lichten, takes as its philosophical and scientific thread the spectrum between natural and virtual light - a fundamental shift that has taken place in the medium of photography over the last thirty years.The selected series include Interiors (1979-1983), Stars (1989-1992) and Nights (1992-1996), as well as parts of Ruffs' most recent series called Negatives (2014-) and Photograms (2012-2014) - a digitally generated simulation of this historical genre. In each of the series, Ruff subjects the photographic medium to systematic analysis: social, political and aesthetic aspects of image production are laid bare, and thereby the history of Modernity as it was initiated by the emergence of photography in the 19th century. As a conceptual photographer, Ruff is not so much interested in photographing reality; he focuses more on portraying the realities of photography.With text contributions by Philippe Van Cauteren, Robert Fleck, Gregor Jansen, Martin Germann, and Valeria Liebermann.